diff --git a/Tools/LambdaTestTool/src/Amazon.Lambda.TestTool/Runtime/LambdaExecutor.cs b/Tools/LambdaTestTool/src/Amazon.Lambda.TestTool/Runtime/LambdaExecutor.cs
index 19ee1dd83..c31b14892 100644
--- a/Tools/LambdaTestTool/src/Amazon.Lambda.TestTool/Runtime/LambdaExecutor.cs
+++ b/Tools/LambdaTestTool/src/Amazon.Lambda.TestTool/Runtime/LambdaExecutor.cs
@@ -194,9 +194,10 @@ public static object[] BuildParameters(ExecutionRequest request, ILambdaContext
                 {
                     parmValues[i] = context;
                 }
-                else if(request.Payload != null)
+                else
                 {
-                    var stream = new MemoryStream(Encoding.UTF8.GetBytes(request.Payload));
+                    var bytes = Encoding.UTF8.GetBytes((request.Payload != null) ? request.Payload : "{}");
+                    var stream = new MemoryStream(bytes);
                     if (request.Function.Serializer != null)
                     {
                         var genericMethodInfo = request.Function.Serializer.GetType()
diff --git a/Tools/LambdaTestTool/tests/Amazon.Lambda.TestTool.Tests.Shared/InvokeFunctionTests.cs b/Tools/LambdaTestTool/tests/Amazon.Lambda.TestTool.Tests.Shared/InvokeFunctionTests.cs
index eb4782be1..4b167c4be 100644
--- a/Tools/LambdaTestTool/tests/Amazon.Lambda.TestTool.Tests.Shared/InvokeFunctionTests.cs
+++ b/Tools/LambdaTestTool/tests/Amazon.Lambda.TestTool.Tests.Shared/InvokeFunctionTests.cs
@@ -86,6 +86,18 @@ public async Task WithGenericParameterTest()
             Assert.Equal("\"Value1,Value2\"", response.Response);
         }
 
+        [Fact]
+        public async Task WithEventParameterTest()
+        {
+
+            var response = await ExecuteFunctionAsync(
+                "FunctionSignatureExamples::FunctionSignatureExamples.InstanceMethods::WithEventParameter",
+                null);
+
+            Assert.True(response.IsSuccess);
+            Assert.Equal("\"WithEventParameter-event-not-null\"", response.Response);
+        }
+
         [Fact]
         public async Task TaskWithNoResultTest()
         {
diff --git a/Tools/LambdaTestTool/tests/LambdaFunctions/netcore21/FunctionSignatureExamples/FunctionSignatureExamples.csproj b/Tools/LambdaTestTool/tests/LambdaFunctions/netcore21/FunctionSignatureExamples/FunctionSignatureExamples.csproj
index f84ad50f0..05a705b79 100644
--- a/Tools/LambdaTestTool/tests/LambdaFunctions/netcore21/FunctionSignatureExamples/FunctionSignatureExamples.csproj
+++ b/Tools/LambdaTestTool/tests/LambdaFunctions/netcore21/FunctionSignatureExamples/FunctionSignatureExamples.csproj
@@ -6,6 +6,7 @@
   <ItemGroup>
     <PackageReference Include="Amazon.Lambda.Core" Version="1.0.0" />
     <PackageReference Include="Amazon.Lambda.Serialization.Json" Version="1.1.0" />
+	<PackageReference Include="Amazon.Lambda.S3Events" Version="1.0.2" />
   </ItemGroup>
   <ItemGroup>
     <DotNetCliToolReference Include="Amazon.Lambda.Tools" Version="2.1.3" />
diff --git a/Tools/LambdaTestTool/tests/LambdaFunctions/netcore21/FunctionSignatureExamples/InstanceMethods.cs b/Tools/LambdaTestTool/tests/LambdaFunctions/netcore21/FunctionSignatureExamples/InstanceMethods.cs
index 397185bbc..fe21726f3 100644
--- a/Tools/LambdaTestTool/tests/LambdaFunctions/netcore21/FunctionSignatureExamples/InstanceMethods.cs
+++ b/Tools/LambdaTestTool/tests/LambdaFunctions/netcore21/FunctionSignatureExamples/InstanceMethods.cs
@@ -4,6 +4,7 @@
 using System.Threading.Tasks;
 
 using Amazon.Lambda.Core;
+using Amazon.Lambda.S3Events;
 
 // Assembly attribute to enable the Lambda function's JSON input to be converted into a .NET class.
 [assembly: LambdaSerializer(typeof(Amazon.Lambda.Serialization.Json.JsonSerializer))]
@@ -44,5 +45,11 @@ public string WithGenericParameter(List<string> values, ILambdaContext context)
             context.Logger.LogLine("Calling WithGenericParameter");
             return string.Join(',', values.ToArray());
         }
+
+        public string WithEventParameter(S3Event evnt, ILambdaContext context)
+        {
+            context.Logger.LogLine("Calling WithEventParameter");
+            return "WithEventParameter-" + ((evnt != null) ? "event-not-null" : "event-null");
+        }
     }
 }
diff --git a/Tools/LambdaTestTool/tests/LambdaFunctions/netcore31/FunctionSignatureExamples/FunctionSignatureExamples.csproj b/Tools/LambdaTestTool/tests/LambdaFunctions/netcore31/FunctionSignatureExamples/FunctionSignatureExamples.csproj
index ab5f4904d..eea78b7d1 100644
--- a/Tools/LambdaTestTool/tests/LambdaFunctions/netcore31/FunctionSignatureExamples/FunctionSignatureExamples.csproj
+++ b/Tools/LambdaTestTool/tests/LambdaFunctions/netcore31/FunctionSignatureExamples/FunctionSignatureExamples.csproj
@@ -6,6 +6,7 @@
   <ItemGroup>
     <PackageReference Include="Amazon.Lambda.Core" Version="1.0.0" />
     <PackageReference Include="Amazon.Lambda.Serialization.Json" Version="1.1.0" />
+	<PackageReference Include="Amazon.Lambda.S3Events" Version="1.0.2" />
   </ItemGroup>
   <ItemGroup>
     <DotNetCliToolReference Include="Amazon.Lambda.Tools" Version="2.1.3" />
diff --git a/Tools/LambdaTestTool/tests/LambdaFunctions/netcore31/FunctionSignatureExamples/InstanceMethods.cs b/Tools/LambdaTestTool/tests/LambdaFunctions/netcore31/FunctionSignatureExamples/InstanceMethods.cs
index 397185bbc..fe21726f3 100644
--- a/Tools/LambdaTestTool/tests/LambdaFunctions/netcore31/FunctionSignatureExamples/InstanceMethods.cs
+++ b/Tools/LambdaTestTool/tests/LambdaFunctions/netcore31/FunctionSignatureExamples/InstanceMethods.cs
@@ -4,6 +4,7 @@
 using System.Threading.Tasks;
 
 using Amazon.Lambda.Core;
+using Amazon.Lambda.S3Events;
 
 // Assembly attribute to enable the Lambda function's JSON input to be converted into a .NET class.
 [assembly: LambdaSerializer(typeof(Amazon.Lambda.Serialization.Json.JsonSerializer))]
@@ -44,5 +45,11 @@ public string WithGenericParameter(List<string> values, ILambdaContext context)
             context.Logger.LogLine("Calling WithGenericParameter");
             return string.Join(',', values.ToArray());
         }
+
+        public string WithEventParameter(S3Event evnt, ILambdaContext context)
+        {
+            context.Logger.LogLine("Calling WithEventParameter");
+            return "WithEventParameter-" + ((evnt != null) ? "event-not-null" : "event-null");
+        }
     }
 }