diff --git a/gtk/gtkrevealer.c b/gtk/gtkrevealer.c
index 511caa8966..f37c24bf13 100644
--- a/gtk/gtkrevealer.c
+++ b/gtk/gtkrevealer.c
@@ -312,10 +312,10 @@ gtk_revealer_get_child_allocation (GtkRevealer   *revealer,
       transition = effective_transition (revealer);
       if (transition == GTK_REVEALER_TRANSITION_TYPE_SLIDE_LEFT ||
           transition == GTK_REVEALER_TRANSITION_TYPE_SLIDE_RIGHT)
-        gtk_widget_get_preferred_width_for_height (child, child_allocation->height, NULL,
+        gtk_widget_get_preferred_width_for_height (child, allocation->height, NULL,
                                                    &child_allocation->width);
       else
-        gtk_widget_get_preferred_height_for_width (child, child_allocation->width, NULL,
+        gtk_widget_get_preferred_height_for_width (child, allocation->width, NULL,
                                                    &child_allocation->height);
     }