diff --git a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactActivityDelegate.java b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactActivityDelegate.java
index 8546a5d6e149b7..61d8e0af79f1e2 100644
--- a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactActivityDelegate.java
+++ b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactActivityDelegate.java
@@ -19,7 +19,6 @@
 import com.facebook.infer.annotation.Assertions;
 import com.facebook.react.bridge.Callback;
 import com.facebook.react.config.ReactFeatureFlags;
-import com.facebook.react.interfaces.ReactHost;
 import com.facebook.react.modules.core.PermissionListener;
 
 /**
diff --git a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactApplication.kt b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactApplication.kt
index 3f572fa149eae4..5131e55c4c5a16 100644
--- a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactApplication.kt
+++ b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactApplication.kt
@@ -8,7 +8,6 @@
 package com.facebook.react
 
 import com.facebook.react.common.annotations.UnstableReactNativeAPI
-import com.facebook.react.interfaces.ReactHost
 
 @OptIn(UnstableReactNativeAPI::class)
 /** Interface that represents an instance of a React Native application */
diff --git a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactDelegate.java b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactDelegate.java
index de1ca03272207c..fab2a26dde2842 100644
--- a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactDelegate.java
+++ b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactDelegate.java
@@ -16,7 +16,6 @@
 import com.facebook.infer.annotation.Assertions;
 import com.facebook.react.config.ReactFeatureFlags;
 import com.facebook.react.devsupport.DoubleTapReloadRecognizer;
-import com.facebook.react.interfaces.ReactHost;
 import com.facebook.react.interfaces.fabric.ReactSurface;
 import com.facebook.react.modules.core.DefaultHardwareBackBtnHandler;
 
diff --git a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/interfaces/ReactHost.kt b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactHost.kt
similarity index 96%
rename from packages/react-native/ReactAndroid/src/main/java/com/facebook/react/interfaces/ReactHost.kt
rename to packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactHost.kt
index 4c5ef17ae36481..a1c3ab897cdfb5 100644
--- a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/interfaces/ReactHost.kt
+++ b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactHost.kt
@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-package com.facebook.react.interfaces
+package com.facebook.react
 
 import android.app.Activity
 import android.content.Context
@@ -13,8 +13,8 @@ import android.os.Bundle
 import com.facebook.react.bridge.ReactContext
 import com.facebook.react.bridge.queue.ReactQueueConfiguration
 import com.facebook.react.common.LifecycleState
-import com.facebook.react.common.annotations.UnstableReactNativeAPI
 import com.facebook.react.devsupport.interfaces.DevSupportManager
+import com.facebook.react.interfaces.TaskInterface
 import com.facebook.react.interfaces.fabric.ReactSurface
 import com.facebook.react.modules.core.DefaultHardwareBackBtnHandler
 
@@ -25,7 +25,6 @@ import com.facebook.react.modules.core.DefaultHardwareBackBtnHandler
  *
  * The implementation of this interface should be Thread Safe
  */
-@UnstableReactNativeAPI
 interface ReactHost {
 
   /** The current [LifecycleState] for React Host */
diff --git a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/bridge/ReactContext.java b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/bridge/ReactContext.java
index dfb1e641215fbf..b57513cb67216e 100644
--- a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/bridge/ReactContext.java
+++ b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/bridge/ReactContext.java
@@ -71,7 +71,7 @@ public interface RCTDeviceEventEmitter extends JavaScriptModule {
   private @Nullable JSExceptionHandler mExceptionHandlerWrapper;
   private @Nullable WeakReference<Activity> mCurrentActivity;
 
-  private @Nullable InteropModuleRegistry mInteropModuleRegistry;
+  protected @Nullable InteropModuleRegistry mInteropModuleRegistry;
   private boolean mIsInitialized = false;
 
   public ReactContext(Context base) {
diff --git a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/common/annotations/UnstableReactNativeAPI.kt b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/common/annotations/UnstableReactNativeAPI.kt
index 3996580c313e4d..5ae0b1779a3b24 100644
--- a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/common/annotations/UnstableReactNativeAPI.kt
+++ b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/common/annotations/UnstableReactNativeAPI.kt
@@ -8,7 +8,7 @@
 package com.facebook.react.common.annotations
 
 @Retention(AnnotationRetention.RUNTIME)
-@Target(AnnotationTarget.CLASS, AnnotationTarget.FUNCTION)
+@Target(AnnotationTarget.CLASS, AnnotationTarget.FUNCTION, AnnotationTarget.PROPERTY)
 @RequiresOptIn(
     level = RequiresOptIn.Level.ERROR,
     message = "This API is experimental and is likely to change or to be removed in the future")
diff --git a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/defaults/DefaultReactHost.kt b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/defaults/DefaultReactHost.kt
index cb8ce917c46680..d481e33c0bd1d9 100644
--- a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/defaults/DefaultReactHost.kt
+++ b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/defaults/DefaultReactHost.kt
@@ -8,20 +8,41 @@
 package com.facebook.react.defaults
 
 import android.content.Context
+import com.facebook.react.JSEngineResolutionAlgorithm
+import com.facebook.react.ReactHost
+import com.facebook.react.ReactNativeHost
 import com.facebook.react.ReactPackage
 import com.facebook.react.bridge.JSBundleLoader
 import com.facebook.react.common.annotations.UnstableReactNativeAPI
 import com.facebook.react.fabric.ComponentFactory
-import com.facebook.react.interfaces.ReactHost
 import com.facebook.react.interfaces.exceptionmanager.ReactJsExceptionHandler
 import com.facebook.react.runtime.JSCInstance
 import com.facebook.react.runtime.ReactHostImpl
 import com.facebook.react.runtime.hermes.HermesInstance
 
-@UnstableReactNativeAPI
+/**
+ * A utility class that allows you to simplify the setup of a [ReactHost] for new apps in Open
+ * Source.
+ *
+ * [ReactHost] is an interface responsible of handling the lifecycle of a React Native app when
+ * running in bridgeless mode.
+ */
 object DefaultReactHost {
   private var reactHost: ReactHost? = null
 
+  /**
+   * Util function to create a default [ReactHost] to be used in your application. This method is
+   * used by the New App template.
+   *
+   * @param context the Android [Context] to use for creating the [ReactHost]
+   * @param packageList the list of [ReactPackage]s to use for creating the [ReactHost]
+   * @param jsMainModulePath the path to your app's main module on Metro. Usually `index` or
+   *   `index.<platform>`
+   * @param jsBundleAssetPath the path to the JS bundle relative to the assets directory. Will be
+   *   composed in a `asset://...` URL
+   * @param isHermesEnabled whether to use Hermes as the JS engine, default to true.
+   */
+  @OptIn(UnstableReactNativeAPI::class)
   @JvmStatic
   fun getDefaultReactHost(
       context: Context,
@@ -47,13 +68,42 @@ object DefaultReactHost {
       // TODO: T164788699 find alternative of accessing ReactHostImpl for initialising reactHost
       reactHost =
           ReactHostImpl(
-              context,
-              defaultReactHostDelegate,
-              componentFactory,
-              true,
-              reactJsExceptionHandler,
-              true)
+                  context,
+                  defaultReactHostDelegate,
+                  componentFactory,
+                  true,
+                  reactJsExceptionHandler,
+                  true)
+              .apply {
+                jsEngineResolutionAlgorithm =
+                    if (isHermesEnabled) {
+                      JSEngineResolutionAlgorithm.HERMES
+                    } else {
+                      JSEngineResolutionAlgorithm.JSC
+                    }
+              }
     }
     return reactHost as ReactHost
   }
+
+  /**
+   * Util function to create a default [ReactHost] to be used in your application. This method is
+   * used by the New App template.
+   *
+   * This method takes in input a [ReactNativeHost] (bridge-mode) and uses its configuration to
+   * create an equivalent [ReactHost] (bridgeless-mode).
+   *
+   * @param context the Android [Context] to use for creating the [ReactHost]
+   * @param reactNativeHost the [ReactNativeHost] to use for creating the [ReactHost]
+   */
+  @JvmStatic
+  fun getDefaultReactHost(
+      context: Context,
+      reactNativeHost: ReactNativeHost,
+  ): ReactHost {
+    require(reactNativeHost is DefaultReactNativeHost) {
+      "You can call getDefaultReactHost only with instances of DefaultReactNativeHost"
+    }
+    return reactNativeHost.toReactHost(context)
+  }
 }
diff --git a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/defaults/DefaultReactNativeHost.kt b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/defaults/DefaultReactNativeHost.kt
index 23c0bada20a220..77cc1a7d1de6b9 100644
--- a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/defaults/DefaultReactNativeHost.kt
+++ b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/defaults/DefaultReactNativeHost.kt
@@ -8,7 +8,9 @@
 package com.facebook.react.defaults
 
 import android.app.Application
+import android.content.Context
 import com.facebook.react.JSEngineResolutionAlgorithm
+import com.facebook.react.ReactHost
 import com.facebook.react.ReactNativeHost
 import com.facebook.react.ReactPackageTurboModuleManagerDelegate
 import com.facebook.react.bridge.JSIModulePackage
@@ -68,4 +70,18 @@ protected constructor(
    */
   protected open val isHermesEnabled: Boolean?
     get() = null
+
+  /**
+   * Converts this [ReactNativeHost] (bridge-mode) to a [ReactHost] (bridgeless-mode).
+   *
+   * @param context the Android [Context] to use for creating the [ReactHost]
+   */
+  fun toReactHost(context: Context): ReactHost =
+      DefaultReactHost.getDefaultReactHost(
+          context,
+          packages,
+          jsMainModuleName,
+          bundleAssetName ?: "index",
+          isHermesEnabled ?: true,
+      )
 }
diff --git a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/runtime/BridgelessReactContext.java b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/runtime/BridgelessReactContext.java
index de5519395dd043..ad4b76d4b549dc 100644
--- a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/runtime/BridgelessReactContext.java
+++ b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/runtime/BridgelessReactContext.java
@@ -22,6 +22,7 @@
 import com.facebook.react.bridge.ReactNoCrashBridgeNotAllowedSoftException;
 import com.facebook.react.bridge.ReactSoftExceptionLogger;
 import com.facebook.react.bridge.WritableNativeArray;
+import com.facebook.react.config.ReactFeatureFlags;
 import com.facebook.react.devsupport.interfaces.DevSupportManager;
 import com.facebook.react.modules.core.DefaultHardwareBackBtnHandler;
 import com.facebook.react.uimanager.events.EventDispatcher;
@@ -49,6 +50,9 @@ class BridgelessReactContext extends ReactApplicationContext implements EventDis
   BridgelessReactContext(Context context, ReactHostImpl host) {
     super(context);
     mReactHost = host;
+    if (ReactFeatureFlags.unstable_useFabricInterop) {
+      initializeInteropModules();
+    }
   }
 
   @Override
@@ -124,6 +128,10 @@ public BridgelessJSModuleInvocationHandler(
 
   @Override
   public <T extends JavaScriptModule> T getJSModule(Class<T> jsInterface) {
+    if (mInteropModuleRegistry != null
+        && mInteropModuleRegistry.shouldReturnInteropModule(jsInterface)) {
+      return mInteropModuleRegistry.getInteropModule(jsInterface);
+    }
     JavaScriptModule interfaceProxy =
         (JavaScriptModule)
             Proxy.newProxyInstance(
diff --git a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/runtime/ReactHostImpl.java b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/runtime/ReactHostImpl.java
index a06f19d7ee44e8..b8ed249d140798 100644
--- a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/runtime/ReactHostImpl.java
+++ b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/runtime/ReactHostImpl.java
@@ -25,6 +25,7 @@
 import com.facebook.infer.annotation.ThreadSafe;
 import com.facebook.react.JSEngineResolutionAlgorithm;
 import com.facebook.react.MemoryPressureRouter;
+import com.facebook.react.ReactHost;
 import com.facebook.react.ReactInstanceEventListener;
 import com.facebook.react.bridge.Callback;
 import com.facebook.react.bridge.JSBundleLoader;
@@ -48,7 +49,6 @@
 import com.facebook.react.devsupport.interfaces.DevSupportManager;
 import com.facebook.react.fabric.ComponentFactory;
 import com.facebook.react.fabric.FabricUIManager;
-import com.facebook.react.interfaces.ReactHost;
 import com.facebook.react.interfaces.TaskInterface;
 import com.facebook.react.interfaces.exceptionmanager.ReactJsExceptionHandler;
 import com.facebook.react.interfaces.fabric.ReactSurface;
diff --git a/packages/react-native/ReactCommon/react/bridging/Object.h b/packages/react-native/ReactCommon/react/bridging/Object.h
index 599b5ceb935788..89e5714b798f0f 100644
--- a/packages/react-native/ReactCommon/react/bridging/Object.h
+++ b/packages/react-native/ReactCommon/react/bridging/Object.h
@@ -31,7 +31,7 @@ struct Bridging<
     std::shared_ptr<T>,
     std::enable_if_t<std::is_base_of_v<jsi::HostObject, T>>> {
   static std::shared_ptr<T> fromJs(jsi::Runtime& rt, const jsi::Object& value) {
-    return value.asHostObject<T>(rt);
+    return value.getHostObject<T>(rt);
   }
 
   static jsi::Object toJs(jsi::Runtime& rt, std::shared_ptr<T> value) {
diff --git a/packages/react-native/template/android/app/src/main/java/com/helloworld/MainApplication.kt b/packages/react-native/template/android/app/src/main/java/com/helloworld/MainApplication.kt
index 7314ad2aad3084..1c38e10c0f7da6 100644
--- a/packages/react-native/template/android/app/src/main/java/com/helloworld/MainApplication.kt
+++ b/packages/react-native/template/android/app/src/main/java/com/helloworld/MainApplication.kt
@@ -3,17 +3,15 @@ package com.helloworld
 import android.app.Application
 import com.facebook.react.PackageList
 import com.facebook.react.ReactApplication
+import com.facebook.react.ReactHost
 import com.facebook.react.ReactNativeHost
 import com.facebook.react.ReactPackage
-import com.facebook.react.common.annotations.UnstableReactNativeAPI
 import com.facebook.react.defaults.DefaultNewArchitectureEntryPoint.load
-import com.facebook.react.defaults.DefaultReactHost
+import com.facebook.react.defaults.DefaultReactHost.getDefaultReactHost
 import com.facebook.react.defaults.DefaultReactNativeHost
 import com.facebook.react.flipper.ReactNativeFlipper
-import com.facebook.react.interfaces.ReactHost
 import com.facebook.soloader.SoLoader
 
-@UnstableReactNativeAPI
 class MainApplication : Application(), ReactApplication {
 
   override val reactNativeHost: ReactNativeHost =
@@ -33,12 +31,7 @@ class MainApplication : Application(), ReactApplication {
       }
 
   override val reactHost: ReactHost
-    get() =
-        DefaultReactHost.getDefaultReactHost(
-            context = this,
-            packageList = PackageList(this).packages,
-            jsMainModulePath = "index",
-            isHermesEnabled = BuildConfig.IS_HERMES_ENABLED)
+    get() = getDefaultReactHost(this.applicationContext, reactNativeHost)
 
   override fun onCreate() {
     super.onCreate()
diff --git a/packages/rn-tester/NativeComponentExample/js/MyNativeView.js b/packages/rn-tester/NativeComponentExample/js/MyNativeView.js
index c74c0f084e7648..fe32899209e87a 100644
--- a/packages/rn-tester/NativeComponentExample/js/MyNativeView.js
+++ b/packages/rn-tester/NativeComponentExample/js/MyNativeView.js
@@ -87,6 +87,7 @@ export default function MyNativeView(props: {}): React.Node {
   const ref = useRef<React.ElementRef<MyNativeViewType> | null>(null);
   const legacyRef = useRef<React.ElementRef<MyLegacyViewType> | null>(null);
   const [opacity, setOpacity] = useState(1.0);
+  const [arrayValues, setArrayValues] = useState([1, 2, 3]);
   const [hsba, setHsba] = useState<HSBA>(new HSBA());
   const [cornerRadiusIndex, setCornerRadiusIndex] = useState<number>(0);
   const [legacyMeasure, setLegacyMeasure] =
@@ -102,7 +103,7 @@ export default function MyNativeView(props: {}): React.Node {
         ref={ref}
         style={{flex: 1}}
         opacity={opacity}
-        values={[0, 1, 2, 3, 4]}
+        values={arrayValues}
         onIntArrayChanged={event => {
           console.log(event.nativeEvent.values);
           console.log(event.nativeEvent.boolValues);
@@ -154,6 +155,11 @@ export default function MyNativeView(props: {}): React.Node {
         title="Set Opacity"
         onPress={() => {
           setOpacity(Math.random());
+          setArrayValues([
+            Math.floor(Math.random() * 100),
+            Math.floor(Math.random() * 100),
+            Math.floor(Math.random() * 100),
+          ]);
         }}
       />
       <Button
diff --git a/packages/rn-tester/android/app/build.gradle b/packages/rn-tester/android/app/build.gradle
index b35e80be387c14..20669ea71b1e0e 100644
--- a/packages/rn-tester/android/app/build.gradle
+++ b/packages/rn-tester/android/app/build.gradle
@@ -146,6 +146,8 @@ android {
         versionName "1.0"
         testBuildType System.getProperty('testBuildType', 'debug')  // This will later be used to control the test apk build type
         testInstrumentationRunner 'androidx.test.runner.AndroidJUnitRunner'
+        buildConfigField("String", "JS_MAIN_MODULE_NAME", "\"js/RNTesterApp.android\"")
+        buildConfigField("String", "BUNDLE_ASSET_NAME", "\"RNTesterApp.android.bundle\"")
     }
     externalNativeBuild {
         cmake {
diff --git a/packages/rn-tester/android/app/src/main/AndroidManifest.xml b/packages/rn-tester/android/app/src/main/AndroidManifest.xml
index 7707683c667d0b..2d6ee37ba1b99d 100644
--- a/packages/rn-tester/android/app/src/main/AndroidManifest.xml
+++ b/packages/rn-tester/android/app/src/main/AndroidManifest.xml
@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest
+  package="com.facebook.react.uiapp"
   xmlns:android="http://schemas.android.com/apk/res/android">
 
   <uses-feature
@@ -15,6 +16,10 @@
     android:name="android.hardware.camera"
     android:required="false" />
 
+  <uses-sdk
+      android:minSdkVersion="23"
+      android:targetSdkVersion="34" />
+
   <uses-permission android:name="android.permission.INTERNET" />
   <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
   <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
diff --git a/packages/rn-tester/android/app/src/main/java/com/facebook/react/uiapp/RNTesterApplication.java b/packages/rn-tester/android/app/src/main/java/com/facebook/react/uiapp/RNTesterApplication.java
deleted file mode 100644
index a1c02a8f005f82..00000000000000
--- a/packages/rn-tester/android/app/src/main/java/com/facebook/react/uiapp/RNTesterApplication.java
+++ /dev/null
@@ -1,211 +0,0 @@
-/*
- * Copyright (c) Meta Platforms, Inc. and affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- */
-
-package com.facebook.react.uiapp;
-
-import android.app.Application;
-import androidx.annotation.NonNull;
-import com.facebook.fbreact.specs.SampleLegacyModule;
-import com.facebook.fbreact.specs.SampleTurboModule;
-import com.facebook.react.JSEngineResolutionAlgorithm;
-import com.facebook.react.ReactApplication;
-import com.facebook.react.ReactNativeHost;
-import com.facebook.react.ReactPackage;
-import com.facebook.react.TurboReactPackage;
-import com.facebook.react.bridge.NativeModule;
-import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.common.annotations.UnstableReactNativeAPI;
-import com.facebook.react.common.assets.ReactFontManager;
-import com.facebook.react.common.mapbuffer.ReadableMapBuffer;
-import com.facebook.react.config.ReactFeatureFlags;
-import com.facebook.react.defaults.DefaultComponentsRegistry;
-import com.facebook.react.defaults.DefaultNewArchitectureEntryPoint;
-import com.facebook.react.defaults.DefaultReactNativeHost;
-import com.facebook.react.fabric.ComponentFactory;
-import com.facebook.react.flipper.ReactNativeFlipper;
-import com.facebook.react.interfaces.ReactHost;
-import com.facebook.react.interfaces.exceptionmanager.ReactJsExceptionHandler;
-import com.facebook.react.module.model.ReactModuleInfo;
-import com.facebook.react.module.model.ReactModuleInfoProvider;
-import com.facebook.react.runtime.ReactHostImpl;
-import com.facebook.react.shell.MainReactPackage;
-import com.facebook.react.uiapp.component.MyLegacyViewManager;
-import com.facebook.react.uiapp.component.MyNativeViewManager;
-import com.facebook.react.uimanager.ViewManager;
-import com.facebook.soloader.SoLoader;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-
-public class RNTesterApplication extends Application implements ReactApplication {
-
-  private ReactHostImpl mReactHost;
-
-  private final ReactNativeHost mReactNativeHost =
-      new DefaultReactNativeHost(this) {
-        @Override
-        public String getJSMainModuleName() {
-          return "js/RNTesterApp.android";
-        }
-
-        @Override
-        public String getBundleAssetName() {
-          return "RNTesterApp.android.bundle";
-        }
-
-        @Override
-        public boolean getUseDeveloperSupport() {
-          return BuildConfig.DEBUG;
-        }
-
-        @Override
-        public List<ReactPackage> getPackages() {
-          return Arrays.<ReactPackage>asList(
-              new MainReactPackage(),
-              new TurboReactPackage() {
-                public NativeModule getModule(
-                    final String name, final ReactApplicationContext reactContext) {
-                  if (!ReactFeatureFlags.useTurboModules) {
-                    return null;
-                  }
-
-                  if (SampleTurboModule.NAME.equals(name)) {
-                    return new SampleTurboModule(reactContext);
-                  }
-
-                  if (SampleLegacyModule.NAME.equals(name)) {
-                    return new SampleLegacyModule(reactContext);
-                  }
-
-                  return null;
-                }
-
-                // Note: Specialized annotation processor for @ReactModule isn't configured in OSS
-                // yet. For now, hardcode this information, though it's not necessary for most
-                // modules.
-                public ReactModuleInfoProvider getReactModuleInfoProvider() {
-                  return new ReactModuleInfoProvider() {
-                    public Map<String, ReactModuleInfo> getReactModuleInfos() {
-                      final Map<String, ReactModuleInfo> moduleInfos = new HashMap<>();
-                      if (ReactFeatureFlags.useTurboModules) {
-                        moduleInfos.put(
-                            SampleTurboModule.NAME,
-                            new ReactModuleInfo(
-                                SampleTurboModule.NAME,
-                                "SampleTurboModule",
-                                false, // canOverrideExistingModule
-                                false, // needsEagerInit
-                                false, // isCxxModule
-                                true // isTurboModule
-                                ));
-
-                        moduleInfos.put(
-                            SampleLegacyModule.NAME,
-                            new ReactModuleInfo(
-                                SampleLegacyModule.NAME,
-                                "SampleLegacyModule",
-                                false, // canOverrideExistingModule
-                                false, // needsEagerInit
-                                false, // isCxxModule
-                                false // isTurboModule
-                                ));
-                      }
-                      return moduleInfos;
-                    }
-                  };
-                }
-              },
-              new ReactPackage() {
-                @NonNull
-                @Override
-                public List<NativeModule> createNativeModules(
-                    @NonNull ReactApplicationContext reactContext) {
-                  return Collections.emptyList();
-                }
-
-                @NonNull
-                @Override
-                public List<ViewManager> createViewManagers(
-                    @NonNull ReactApplicationContext reactContext) {
-                  List<ViewManager> viewManagers = new ArrayList<>();
-                  viewManagers.add(new MyNativeViewManager());
-                  viewManagers.add(new MyLegacyViewManager(reactContext));
-                  return viewManagers;
-                }
-              });
-        }
-
-        @Override
-        protected boolean isNewArchEnabled() {
-          return BuildConfig.IS_NEW_ARCHITECTURE_ENABLED;
-        }
-
-        @Override
-        protected Boolean isHermesEnabled() {
-          return BuildConfig.IS_HERMES_ENABLED_IN_FLAVOR;
-        }
-      };
-
-  @Override
-  public void onCreate() {
-    ReactFontManager.getInstance().addCustomFont(this, "Rubik", R.font.rubik);
-    super.onCreate();
-    SoLoader.init(this, /* native exopackage */ false);
-    if (BuildConfig.IS_NEW_ARCHITECTURE_ENABLED) {
-      DefaultNewArchitectureEntryPoint.load();
-    }
-    if (ReactFeatureFlags.enableBridgelessArchitecture) {
-      // TODO: initialize Flipper for Bridgeless
-    } else {
-      ReactNativeFlipper.initializeFlipper(this, getReactNativeHost().getReactInstanceManager());
-    }
-  }
-
-  @Override
-  public ReactNativeHost getReactNativeHost() {
-    return mReactNativeHost;
-  }
-
-  @Override
-  @UnstableReactNativeAPI
-  public ReactHost getReactHost() {
-    if (mReactHost == null) {
-      // Create an instance of ReactHost to manager the instance of ReactInstance,
-      // which is similar to how we use ReactNativeHost to manager instance of ReactInstanceManager
-      RNTesterReactHostDelegate reactHostDelegate =
-          new RNTesterReactHostDelegate(getApplicationContext());
-      RNTesterReactJsExceptionHandler reactJsExceptionHandler =
-          new RNTesterReactJsExceptionHandler();
-
-      ComponentFactory componentFactory = new ComponentFactory();
-      DefaultComponentsRegistry.register(componentFactory);
-      mReactHost =
-          new ReactHostImpl(
-              this.getApplicationContext(),
-              reactHostDelegate,
-              componentFactory,
-              true,
-              reactJsExceptionHandler,
-              true);
-      if (BuildConfig.IS_HERMES_ENABLED_IN_FLAVOR) {
-        mReactHost.setJSEngineResolutionAlgorithm(JSEngineResolutionAlgorithm.HERMES);
-      } else {
-        mReactHost.setJSEngineResolutionAlgorithm(JSEngineResolutionAlgorithm.JSC);
-      }
-      reactHostDelegate.setReactHost(mReactHost);
-    }
-    return mReactHost;
-  }
-
-  @UnstableReactNativeAPI
-  public static class RNTesterReactJsExceptionHandler implements ReactJsExceptionHandler {
-    public void reportJsException(ReadableMapBuffer errorMap) {}
-  }
-};
diff --git a/packages/rn-tester/android/app/src/main/java/com/facebook/react/uiapp/RNTesterApplication.kt b/packages/rn-tester/android/app/src/main/java/com/facebook/react/uiapp/RNTesterApplication.kt
new file mode 100644
index 00000000000000..9f3c5cd27e746e
--- /dev/null
+++ b/packages/rn-tester/android/app/src/main/java/com/facebook/react/uiapp/RNTesterApplication.kt
@@ -0,0 +1,137 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+package com.facebook.react.uiapp
+
+import android.app.Application
+import com.facebook.fbreact.specs.SampleLegacyModule
+import com.facebook.fbreact.specs.SampleTurboModule
+import com.facebook.react.ReactApplication
+import com.facebook.react.ReactHost
+import com.facebook.react.ReactNativeHost
+import com.facebook.react.ReactPackage
+import com.facebook.react.TurboReactPackage
+import com.facebook.react.ViewManagerOnDemandReactPackage
+import com.facebook.react.bridge.NativeModule
+import com.facebook.react.bridge.ReactApplicationContext
+import com.facebook.react.common.assets.ReactFontManager
+import com.facebook.react.config.ReactFeatureFlags
+import com.facebook.react.defaults.DefaultNewArchitectureEntryPoint.load
+import com.facebook.react.defaults.DefaultReactHost
+import com.facebook.react.defaults.DefaultReactNativeHost
+import com.facebook.react.flipper.ReactNativeFlipper.initializeFlipper
+import com.facebook.react.module.model.ReactModuleInfo
+import com.facebook.react.module.model.ReactModuleInfoProvider
+import com.facebook.react.shell.MainReactPackage
+import com.facebook.react.uiapp.component.MyLegacyViewManager
+import com.facebook.react.uiapp.component.MyNativeViewManager
+import com.facebook.react.uimanager.ReactShadowNode
+import com.facebook.react.uimanager.ViewManager
+import com.facebook.soloader.SoLoader
+
+class RNTesterApplication : Application(), ReactApplication {
+  override val reactNativeHost: ReactNativeHost by lazy {
+    object : DefaultReactNativeHost(this) {
+      public override fun getJSMainModuleName(): String = BuildConfig.JS_MAIN_MODULE_NAME
+
+      public override fun getBundleAssetName(): String = BuildConfig.BUNDLE_ASSET_NAME
+
+      override fun getUseDeveloperSupport(): Boolean = BuildConfig.DEBUG
+
+      public override fun getPackages(): List<ReactPackage> {
+        return listOf(
+            MainReactPackage(),
+            object : TurboReactPackage() {
+              override fun getModule(
+                  name: String,
+                  reactContext: ReactApplicationContext
+              ): NativeModule? {
+                if (!ReactFeatureFlags.useTurboModules) {
+                  return null
+                }
+                if (SampleTurboModule.NAME == name) {
+                  return SampleTurboModule(reactContext)
+                }
+                if (SampleLegacyModule.NAME == name) {
+                  return SampleLegacyModule(reactContext)
+                }
+                return null
+              }
+
+              // Note: Specialized annotation processor for @ReactModule isn't configured in OSS
+              // yet. For now, hardcode this information, though it's not necessary for most
+              // modules.
+              override fun getReactModuleInfoProvider(): ReactModuleInfoProvider =
+                  ReactModuleInfoProvider {
+                    if (ReactFeatureFlags.useTurboModules) {
+                      mapOf(
+                          SampleTurboModule.NAME to
+                              ReactModuleInfo(
+                                  SampleTurboModule.NAME,
+                                  "SampleTurboModule",
+                                  false, // canOverrideExistingModule
+                                  false, // needsEagerInit
+                                  false, // isCxxModule
+                                  true // isTurboModule
+                                  ),
+                          SampleLegacyModule.NAME to
+                              ReactModuleInfo(
+                                  SampleLegacyModule.NAME,
+                                  "SampleLegacyModule",
+                                  false, // canOverrideExistingModule
+                                  false, // needsEagerInit
+                                  false, // isCxxModule
+                                  false // isTurboModule
+                                  ))
+                    } else {
+                      emptyMap()
+                    }
+                  }
+            },
+            object : ReactPackage, ViewManagerOnDemandReactPackage {
+              override fun createNativeModules(
+                  reactContext: ReactApplicationContext
+              ): List<NativeModule> = emptyList()
+
+              override fun getViewManagerNames(reactContext: ReactApplicationContext) =
+                  listOf("RNTMyNativeView", "RNTMyLegacyNativeView")
+
+              override fun createViewManagers(
+                  reactContext: ReactApplicationContext
+              ): List<ViewManager<*, *>> =
+                  listOf(MyNativeViewManager(), MyLegacyViewManager(reactContext))
+
+              override fun createViewManager(
+                  reactContext: ReactApplicationContext,
+                  viewManagerName: String
+              ): ViewManager<*, out ReactShadowNode<*>> =
+                  if (viewManagerName == "RNTMyNativeView") {
+                    MyNativeViewManager()
+                  } else {
+                    MyLegacyViewManager(reactContext)
+                  }
+            })
+      }
+
+      override val isNewArchEnabled: Boolean = BuildConfig.IS_NEW_ARCHITECTURE_ENABLED
+      override val isHermesEnabled: Boolean = BuildConfig.IS_HERMES_ENABLED_IN_FLAVOR
+    }
+  }
+
+  override val reactHost: ReactHost
+    get() = DefaultReactHost.getDefaultReactHost(this.applicationContext, reactNativeHost)
+
+  override fun onCreate() {
+    ReactFontManager.getInstance().addCustomFont(this, "Rubik", R.font.rubik)
+    super.onCreate()
+    SoLoader.init(this, /* native exopackage */ false)
+    if (BuildConfig.IS_NEW_ARCHITECTURE_ENABLED) {
+      load()
+    }
+    initializeFlipper(this, reactNativeHost.reactInstanceManager)
+  }
+}
diff --git a/packages/rn-tester/android/app/src/main/java/com/facebook/react/uiapp/RNTesterReactHostDelegate.kt b/packages/rn-tester/android/app/src/main/java/com/facebook/react/uiapp/RNTesterReactHostDelegate.kt
deleted file mode 100644
index aa0111fec1328f..00000000000000
--- a/packages/rn-tester/android/app/src/main/java/com/facebook/react/uiapp/RNTesterReactHostDelegate.kt
+++ /dev/null
@@ -1,122 +0,0 @@
-/*
- * Copyright (c) Meta Platforms, Inc. and affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- */
-
-package com.facebook.react.uiapp
-
-import android.content.Context
-import com.facebook.fbreact.specs.SampleLegacyModule
-import com.facebook.fbreact.specs.SampleTurboModule
-import com.facebook.react.JSEngineResolutionAlgorithm
-import com.facebook.react.ReactPackage
-import com.facebook.react.ReactPackageTurboModuleManagerDelegate
-import com.facebook.react.TurboReactPackage
-import com.facebook.react.bridge.JSBundleLoader
-import com.facebook.react.bridge.NativeModule
-import com.facebook.react.bridge.ReactApplicationContext
-import com.facebook.react.common.annotations.UnstableReactNativeAPI
-import com.facebook.react.config.ReactFeatureFlags
-import com.facebook.react.defaults.DefaultTurboModuleManagerDelegate
-import com.facebook.react.fabric.ReactNativeConfig
-import com.facebook.react.module.model.ReactModuleInfo
-import com.facebook.react.module.model.ReactModuleInfoProvider
-import com.facebook.react.runtime.BindingsInstaller
-import com.facebook.react.runtime.JSCInstance
-import com.facebook.react.runtime.JSEngineInstance
-import com.facebook.react.runtime.ReactHostDelegate
-import com.facebook.react.runtime.ReactHostImpl
-import com.facebook.react.runtime.hermes.HermesInstance
-import com.facebook.react.shell.MainReactPackage
-import com.facebook.react.turbomodule.core.TurboModuleManager
-import com.facebook.react.uiapp.component.MyLegacyViewManager
-import com.facebook.react.uiapp.component.MyNativeViewManager
-import com.facebook.react.uimanager.ViewManager
-
-@UnstableReactNativeAPI
-class RNTesterReactHostDelegate internal constructor(context: Context) : ReactHostDelegate {
-  var reactHost: ReactHostImpl? = null
-
-  override val jsMainModulePath: String = "js/RNTesterApp.android"
-
-  override val jsBundleLoader: JSBundleLoader =
-      JSBundleLoader.createAssetLoader(context, "assets://RNTesterApp.android.bundle", true)
-
-  @get:Synchronized override val bindingsInstaller: BindingsInstaller? = null
-
-  override val turboModuleManagerDelegateBuilder: ReactPackageTurboModuleManagerDelegate.Builder =
-      DefaultTurboModuleManagerDelegate.Builder()
-
-  override val jsEngineInstance: JSEngineInstance =
-      if (reactHost?.jsEngineResolutionAlgorithm == JSEngineResolutionAlgorithm.JSC) {
-        JSCInstance()
-      } else {
-        HermesInstance()
-      }
-
-  override fun handleInstanceException(error: Exception) {}
-
-  override fun getReactNativeConfig(turboModuleManager: TurboModuleManager): ReactNativeConfig =
-      ReactNativeConfig.DEFAULT_CONFIG
-
-  override val reactPackages: List<ReactPackage> by lazy {
-    listOf(
-        MainReactPackage(),
-        object : TurboReactPackage() {
-          override fun getModule(
-              name: String,
-              reactContext: ReactApplicationContext
-          ): NativeModule? =
-              when {
-                !ReactFeatureFlags.useTurboModules -> null
-                name == SampleTurboModule.NAME -> SampleTurboModule(reactContext)
-                name == SampleLegacyModule.NAME -> SampleLegacyModule(reactContext)
-                else -> null
-              }
-
-          // Note: Specialized annotation processor for @ReactModule isn't
-          // configured in OSS
-          // yet. For now, hardcode this information, though it's not necessary
-          // for most modules
-          override fun getReactModuleInfoProvider(): ReactModuleInfoProvider =
-              ReactModuleInfoProvider {
-                if (ReactFeatureFlags.useTurboModules) {
-                  mapOf(
-                      SampleTurboModule.NAME to
-                          ReactModuleInfo(
-                              SampleTurboModule.NAME,
-                              "SampleTurboModule",
-                              false, // canOverrideExistingModule
-                              false, // needsEagerInit
-                              false, // isCxxModule
-                              true // isTurboModule
-                              ),
-                      SampleLegacyModule.NAME to
-                          ReactModuleInfo(
-                              SampleLegacyModule.NAME,
-                              "SampleLegacyModule",
-                              false, // canOverrideExistingModule
-                              false, // needsEagerInit
-                              false, // isCxxModule
-                              false // isTurboModule
-                              ),
-                  )
-                } else {
-                  emptyMap()
-                }
-              }
-        },
-        object : ReactPackage {
-          override fun createNativeModules(
-              reactContext: ReactApplicationContext
-          ): List<NativeModule> = emptyList()
-
-          override fun createViewManagers(
-              reactContext: ReactApplicationContext
-          ): List<ViewManager<*, *>> =
-              listOf(MyNativeViewManager(), MyLegacyViewManager(reactContext))
-        })
-  }
-}
diff --git a/packages/rn-tester/android/app/src/main/java/com/facebook/react/uiapp/component/MyLegacyViewManager.kt b/packages/rn-tester/android/app/src/main/java/com/facebook/react/uiapp/component/MyLegacyViewManager.kt
index 5845e85af5390f..1ff6b782db7b5c 100644
--- a/packages/rn-tester/android/app/src/main/java/com/facebook/react/uiapp/component/MyLegacyViewManager.kt
+++ b/packages/rn-tester/android/app/src/main/java/com/facebook/react/uiapp/component/MyLegacyViewManager.kt
@@ -26,8 +26,8 @@ internal class MyLegacyViewManager(reactContext: ReactApplicationContext) :
 
   override fun getName(): String = REACT_CLASS
 
-  override fun createViewInstance(reactContext: ThemedReactContext): MyNativeView =
-      MyNativeView(reactContext).apply { setBackgroundColor(Color.RED) }
+  override fun createViewInstance(themedReactContext: ThemedReactContext): MyNativeView =
+      MyNativeView(themedReactContext).apply { setBackgroundColor(Color.RED) }
 
   @ReactProp(name = ViewProps.OPACITY, defaultFloat = 1f)
   override fun setOpacity(view: MyNativeView, opacity: Float) {
diff --git a/packages/rn-tester/android/app/src/main/java/com/facebook/react/uiapp/component/MyNativeView.kt b/packages/rn-tester/android/app/src/main/java/com/facebook/react/uiapp/component/MyNativeView.kt
index 78584e08f89d69..c9365d728025c7 100644
--- a/packages/rn-tester/android/app/src/main/java/com/facebook/react/uiapp/component/MyNativeView.kt
+++ b/packages/rn-tester/android/app/src/main/java/com/facebook/react/uiapp/component/MyNativeView.kt
@@ -7,7 +7,6 @@
 
 package com.facebook.react.uiapp.component
 
-import android.content.Context
 import android.graphics.Color
 import android.graphics.drawable.GradientDrawable
 import android.view.View
@@ -15,13 +14,15 @@ import com.facebook.react.bridge.Arguments
 import com.facebook.react.bridge.ReactContext
 import com.facebook.react.bridge.WritableArray
 import com.facebook.react.bridge.WritableMap
+import com.facebook.react.uimanager.ThemedReactContext
 import com.facebook.react.uimanager.UIManagerHelper
 import com.facebook.react.uimanager.events.Event
 import com.facebook.react.uimanager.events.RCTEventEmitter
 
-class MyNativeView(context: Context) : View(context) {
+class MyNativeView(context: ThemedReactContext) : View(context) {
   private var currentColor = 0
   private var background: GradientDrawable = GradientDrawable()
+  private var reactContext: ReactContext = context.reactApplicationContext
 
   override fun setBackgroundColor(color: Int) {
     if (color != currentColor) {
@@ -33,13 +34,14 @@ class MyNativeView(context: Context) : View(context) {
   }
 
   fun setCornerRadius(cornerRadius: Float) {
-    background.setCornerRadius(cornerRadius)
+    background.cornerRadius = cornerRadius
     setBackground(background)
   }
 
   private fun emitNativeEvent(color: Int) {
     val event = Arguments.createMap()
     val hsv = FloatArray(3)
+    Color.colorToHSV(color, hsv)
     val backgroundColor =
         Arguments.createMap().apply {
           putDouble("hue", hsv[0].toDouble())
@@ -48,10 +50,8 @@ class MyNativeView(context: Context) : View(context) {
           putDouble("alpha", Color.alpha(color).toDouble())
         }
 
-    Color.colorToHSV(color, hsv)
     event.putMap("backgroundColor", backgroundColor)
 
-    val reactContext = context as ReactContext
     reactContext.getJSModule(RCTEventEmitter::class.java).receiveEvent(id, "onColorChanged", event)
   }
 
@@ -110,7 +110,7 @@ class MyNativeView(context: Context) : View(context) {
       viewId: Int,
       private val payload: WritableMap
   ) : Event<OnIntArrayChangedEvent>(surfaceId, viewId) {
-    override fun getEventName() = "onIntArrayChanged"
+    override fun getEventName() = "topIntArrayChanged"
 
     override fun getEventData() = payload
   }
diff --git a/packages/rn-tester/android/app/src/main/java/com/facebook/react/uiapp/component/MyNativeViewManager.kt b/packages/rn-tester/android/app/src/main/java/com/facebook/react/uiapp/component/MyNativeViewManager.kt
index 35635167b4104f..938d27f4c46ad5 100644
--- a/packages/rn-tester/android/app/src/main/java/com/facebook/react/uiapp/component/MyNativeViewManager.kt
+++ b/packages/rn-tester/android/app/src/main/java/com/facebook/react/uiapp/component/MyNativeViewManager.kt
@@ -60,7 +60,7 @@ internal class MyNativeViewManager :
   override fun getExportedCustomBubblingEventTypeConstants(): Map<String, Any> =
       MapBuilder.builder<String, Any>()
           .put(
-              "onIntArrayChanged",
+              "topIntArrayChanged",
               MapBuilder.of<String, Any>(
                   "phasedRegistrationNames",
                   MapBuilder.of(