diff --git a/tests/generator-Tests/Unit-Tests/DefaultInterfaceMethodsTests.cs b/tests/generator-Tests/Unit-Tests/DefaultInterfaceMethodsTests.cs
index 25f737f5c..39f40d380 100644
--- a/tests/generator-Tests/Unit-Tests/DefaultInterfaceMethodsTests.cs
+++ b/tests/generator-Tests/Unit-Tests/DefaultInterfaceMethodsTests.cs
@@ -431,5 +431,36 @@ public void DontInvalidateInterfaceDueToStaticOrDefaultMethods ()
 			Assert.False (generated.Contains ("StaticMethod"));
 			Assert.False (generated.Contains ("DefaultMethod"));
 		}
+
+		[Test]
+		public void GenerateProperNestedInterfaceSignatures ()
+		{
+			// https://github.com/xamarin/java.interop/issues/661
+			// Ensure that when we write the invoker type for a nested default interface method
+			// we use `/` to denote nested as needed by Type.GetType ()
+			var xml = @"<api>
+			  <package name='java.lang' jni-name='java/lang'>
+			    <class abstract='false' deprecated='not deprecated' final='false' name='Object' static='false' visibility='public' jni-signature='Ljava/lang/EmptyOverrideClass;' />
+			  </package>
+			  <package name='com.xamarin.android' jni-name='com/xamarin/android'>
+			    <class extends='java.lang.Object' abstract='true' deprecated='not deprecated' final='false' name='Application' static='true' visibility='public' jni-signature='Landroid/app/Application$ActivityLifecycleCallbacks;' />
+			    <interface abstract='true' deprecated='not deprecated' final='false' name='Application.ActivityLifecycleInterface' static='true' visibility='public' jni-signature='Landroid/app/Application$ActivityLifecycleCallbacks;'>
+			      <method abstract='false' deprecated='not deprecated' final='false' name='onActivityDestroyed' jni-signature='(Landroid/app/Activity;)V' bridge='false' native='false' return='void' jni-return='V' static='false' synchronized='false' synthetic='false' visibility='public'>
+			        <parameter name='activity' type='int' jni-type='I' not-null='true'></parameter>
+			      </method>
+			    </interface>
+			  </package>
+			</api>";
+
+			var gens = ParseApiDefinition (xml);
+			var iface = gens[1].NestedTypes.OfType<InterfaceGen> ().Single ();
+
+			generator.WriteInterface (iface, string.Empty, new GenerationInfo (string.Empty, string.Empty, "MyAssembly"));
+
+			var generated = writer.ToString ();
+
+			Assert.True (generated.Contains ("GetOnActivityDestroyed_IHandler:Com.Xamarin.Android.Application/IActivityLifecycleInterface, MyAssembly"));
+			Assert.False (generated.Contains ("GetOnActivityDestroyed_IHandler:Com.Xamarin.Android.Application.IActivityLifecycleInterface, MyAssembly"));
+		}
 	}
 }
diff --git a/tools/generator/Java.Interop.Tools.Generator.ObjectModel/Method.cs b/tools/generator/Java.Interop.Tools.Generator.ObjectModel/Method.cs
index 6ad71a4e0..cc745390c 100644
--- a/tools/generator/Java.Interop.Tools.Generator.ObjectModel/Method.cs
+++ b/tools/generator/Java.Interop.Tools.Generator.ObjectModel/Method.cs
@@ -126,7 +126,7 @@ internal string GetAdapterName (CodeGenerationOptions opt, string adapter)
 		}
 
 		// Connectors for DIM are defined on the interface, not the implementing type
-		public string GetConnectorNameFull (CodeGenerationOptions opt) => ConnectorName + (opt.SupportDefaultInterfaceMethods && IsInterfaceDefaultMethod ? $":{DeclaringType.FullName}, " + (AssemblyName ?? opt.AssemblyName) : string.Empty);
+		public string GetConnectorNameFull (CodeGenerationOptions opt) => ConnectorName + (opt.SupportDefaultInterfaceMethods && IsInterfaceDefaultMethod ? $":{DeclaringType.AssemblyQualifiedName}, " + (AssemblyName ?? opt.AssemblyName) : string.Empty);
 
 		internal string GetDelegateType (CodeGenerationOptions opt) => opt.GetJniMarshalDelegate (this);