diff --git a/include/objbase.h b/include/objbase.h
index fb2b99a1f3d..a470af0cf18 100644
--- a/include/objbase.h
+++ b/include/objbase.h
@@ -272,6 +272,15 @@
 
 #endif  /* __cplusplus && !CINTERFACE */
 
+#ifndef __IRpcStubBuffer_FWD_DEFINED__
+#define __IRpcStubBuffer_FWD_DEFINED__
+typedef interface IRpcStubBuffer IRpcStubBuffer;
+#endif
+#ifndef __IRpcChannelBuffer_FWD_DEFINED__
+#define __IRpcChannelBuffer_FWD_DEFINED__
+typedef interface IRpcChannelBuffer IRpcChannelBuffer;
+#endif
+
 #include <objidl.h>
 
 #ifndef RC_INVOKED
diff --git a/tools/widl/header.c b/tools/widl/header.c
index 90b93caa1f6..88621f32af4 100644
--- a/tools/widl/header.c
+++ b/tools/widl/header.c
@@ -690,8 +690,8 @@ static void write_method_proto(type_t *iface)
       fprintf(header, "void __RPC_STUB %s_", iface->name);
       write_name(header,def);
       fprintf(header, "_Stub(\n");
-      fprintf(header, "    interface IRpcStubBuffer* This,\n");
-      fprintf(header, "    interface IRpcChannelBuffer* pRpcChannelBuffer,\n");
+      fprintf(header, "    IRpcStubBuffer* This,\n");
+      fprintf(header, "    IRpcChannelBuffer* pRpcChannelBuffer,\n");
       fprintf(header, "    PRPC_MESSAGE pRpcMessage,\n");
       fprintf(header, "    DWORD* pdwStubPhase);\n");