diff --git a/gtk/gtkfilechooserbutton.h b/gtk/gtkfilechooserbutton.h
index 761153332a..4d9311726f 100644
--- a/gtk/gtkfilechooserbutton.h
+++ b/gtk/gtkfilechooserbutton.h
@@ -46,7 +46,7 @@ struct _GtkFileChooserButton
   /*< private >*/
   GtkHBox parent;
 
-  GtkFileChooserButtonPrivate *priv;
+  GtkFileChooserButtonPrivate *GSEAL (priv);
 };
 
 struct _GtkFileChooserButtonClass