diff --git a/include/objidl.idl b/include/objidl.idl
index 1b75ba001a9..02de2ef12ef 100644
--- a/include/objidl.idl
+++ b/include/objidl.idl
@@ -215,6 +215,18 @@ interface IMallocSpy : IUnknown
   void PostHeapMinimize();
 }
 
+[
+  local,
+  object,
+  uuid(00000021-0000-0000-C000-000000000046)
+]
+interface IInternalUnknown : IUnknown
+{
+  HRESULT QueryInternalInterface(
+    [in] REFIID riid,
+    [out] void **ppv);
+}
+
 [
   object,
   uuid(00000100-0000-0000-C000-000000000046),