diff --git a/gtk/gtkfixed.c b/gtk/gtkfixed.c
index bdb8e9570f..355929ecc7 100644
--- a/gtk/gtkfixed.c
+++ b/gtk/gtkfixed.c
@@ -235,6 +235,7 @@ gtk_fixed_put (GtkFixed  *fixed,
 
   g_return_if_fail (GTK_IS_FIXED (fixed));
   g_return_if_fail (GTK_IS_WIDGET (widget));
+  g_return_if_fail (_gtk_widget_get_parent (widget) == NULL);
 
   priv = fixed->priv;