diff --git a/mpeg/id3v2/id3v2frame.h b/mpeg/id3v2/id3v2frame.h
index 4e12dc21..392bb71a 100644
--- a/mpeg/id3v2/id3v2frame.h
+++ b/mpeg/id3v2/id3v2frame.h
@@ -182,6 +182,7 @@ namespace TagLib {
       Frame &operator=(const Frame &);
 
       class FramePrivate;
+      friend class FramePrivate;
       FramePrivate *d;
     };