diff --git a/src/RestSharp/Parameters/Parameter.cs b/src/RestSharp/Parameters/Parameter.cs
index fe260f3c6..0c5928d32 100644
--- a/src/RestSharp/Parameters/Parameter.cs
+++ b/src/RestSharp/Parameters/Parameter.cs
@@ -34,7 +34,7 @@ public static Parameter CreateParameter(string? name, object? value, ParameterTy
             ParameterType.GetOrPost   => new GetOrPostParameter(name!, value?.ToString(), encode),
             ParameterType.UrlSegment  => new UrlSegmentParameter(name!, value?.ToString()!, encode),
             ParameterType.HttpHeader  => new HeaderParameter(name, value?.ToString()),
-            ParameterType.RequestBody => new BodyParameter(name, value!, Serializers.ContentType.Plain),
+            ParameterType.RequestBody => new BodyParameter("", value!, string.IsNullOrEmpty(name) ? Serializers.ContentType.Plain : name!),
             ParameterType.QueryString => new QueryParameter(name!, value?.ToString(), encode),
             _                         => throw new ArgumentOutOfRangeException(nameof(type), type, null)
         };
diff --git a/test/RestSharp.Tests.Integrated/MultipartFormDataTests.cs b/test/RestSharp.Tests.Integrated/MultipartFormDataTests.cs
index 4ea0e3c8b..305a2a9b6 100644
--- a/test/RestSharp.Tests.Integrated/MultipartFormDataTests.cs
+++ b/test/RestSharp.Tests.Integrated/MultipartFormDataTests.cs
@@ -69,7 +69,7 @@ public async Task AlwaysMultipartFormData_WithParameter_Execute() {
             Method                  = Method.Post
         };
 
-        request.AddParameter("title", "test", ParameterType.RequestBody);
+        request.AddParameter("", "test", ParameterType.RequestBody);
 
         var response = await _client.ExecuteAsync(request);
 
diff --git a/test/RestSharp.Tests/RestContentTests.cs b/test/RestSharp.Tests/RestContentTests.cs
index 2e7744988..5ee6ae3aa 100644
--- a/test/RestSharp.Tests/RestContentTests.cs
+++ b/test/RestSharp.Tests/RestContentTests.cs
@@ -12,4 +12,17 @@ public void RestContent_CaseInsensitiveHeaders() {
 
         httpContent.Headers.ContentType!.MediaType.Should().Be(myContentType);
     }
+
+    [Fact]
+    public void RestContent_supports_manual_json_body() {
+        const string myContentType = "application/json";
+        const string myJsonString = "[]";
+
+        var request = new RestRequest("resource").AddParameter(myContentType, myJsonString, ParameterType.RequestBody);
+        var content = new RequestContent(new RestClient(), request);
+
+        var httpContent = content.BuildContent();
+
+        httpContent.Headers.ContentType!.MediaType.Should().Be(myContentType);
+    }
 }