diff --git a/ChangeLog b/ChangeLog
index c2dd15fb3..63a5d194a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2009-05-01  Mike Kestner  <mkestner@novell.com>
+
+	* glib/Object.cs: get gtype from instance data.
+	* glib/Value.cs: use instance NativeType when initing for props.
+	[Fixes #500157] Patch by Sebastian Dröge.
+
 2009-04-28  Mike Kestner  <mkestner@novell.com>
 
 	* generator/Parameters.cs: ref parameter marshaling fix.
diff --git a/glib/Object.cs b/glib/Object.cs
index 882388c84..c0e6eb8fb 100644
--- a/glib/Object.cs
+++ b/glib/Object.cs
@@ -186,7 +186,7 @@ namespace GLib {
 		}
 
 		struct GTypeClass {
-			IntPtr gtype;
+			public IntPtr gtype;
 		}
 
 		struct GObjectClass {
@@ -323,7 +323,9 @@ namespace GLib {
 
 		protected GType LookupGType ()
 		{
-			return LookupGType (GetType ());
+			GTypeInstance obj = (GTypeInstance) Marshal.PtrToStructure (Handle, typeof (GTypeInstance));
+			GTypeClass klass = (GTypeClass) Marshal.PtrToStructure (obj.g_class, typeof (GTypeClass));
+			return new GLib.GType (klass.gtype);
 		}
 
 		protected internal static GType LookupGType (System.Type t)
diff --git a/glib/Value.cs b/glib/Value.cs
index f8abcc50b..6d143f036 100755
--- a/glib/Value.cs
+++ b/glib/Value.cs
@@ -518,7 +518,7 @@ namespace GLib {
 
 		void InitForProperty (Object obj, string name)
 		{
-			GType gtype = Object.LookupGType (obj.GetType ());
+			GType gtype = obj.NativeType;
 			InitForProperty (gtype, name);
 		}