diff --git a/libgimpwidgets/gimppickbutton-default.c b/libgimpwidgets/gimppickbutton-default.c
index 2118f64d9a..6fda2c80ba 100644
--- a/libgimpwidgets/gimppickbutton-default.c
+++ b/libgimpwidgets/gimppickbutton-default.c
@@ -54,7 +54,7 @@ static void       gimp_pick_button_pick          (GdkScreen      *screen,
                                                   GimpPickButton *button);
 
 
-void              gimp_pick_button_clicked       (GtkButton      *gtk_button);
+void              _gimp_pick_button_clicked      (GtkButton      *gtk_button);
 
 static GdkCursor *
 make_cursor (GdkDisplay *display)
@@ -225,7 +225,7 @@ gimp_pick_button_pick (GdkScreen      *screen,
 
 /* entry point to this file, called from gimppickbutton.c */
 void
-gimp_pick_button_clicked (GtkButton *gtk_button)
+_gimp_pick_button_clicked (GtkButton *gtk_button)
 {
   GimpPickButton *button = GIMP_PICK_BUTTON (gtk_button);
   GtkWidget      *widget;
diff --git a/libgimpwidgets/gimppickbutton-quartz.c b/libgimpwidgets/gimppickbutton-quartz.c
index a14cd90633..07bb86a918 100644
--- a/libgimpwidgets/gimppickbutton-quartz.c
+++ b/libgimpwidgets/gimppickbutton-quartz.c
@@ -34,7 +34,7 @@
 #endif
 
 
-void              gimp_pick_button_clicked       (GtkButton      *gtk_button);
+void              _gimp_pick_button_clicked      (GtkButton      *gtk_button);
 
 
 @interface GimpPickWindowController : NSObject
@@ -400,7 +400,7 @@ void              gimp_pick_button_clicked       (GtkButton      *gtk_button);
 
 /* entrypoint to this file, called from gimppickbutton.c */
 void
-gimp_pick_button_clicked (GtkButton *gtk_button)
+_gimp_pick_button_clicked (GtkButton *gtk_button)
 {
   GimpPickButton           *button = GIMP_PICK_BUTTON (gtk_button);
   GimpPickWindowController *controller;
diff --git a/libgimpwidgets/gimppickbutton.c b/libgimpwidgets/gimppickbutton.c
index 94d5db8c1d..9e05153ace 100644
--- a/libgimpwidgets/gimppickbutton.c
+++ b/libgimpwidgets/gimppickbutton.c
@@ -51,7 +51,7 @@ enum
 };
 
 /* entry point to gimppickbutton-{default,quartz}.c */
-extern void       gimp_pick_button_clicked       (GtkButton      *gtk_button);
+extern void       _gimp_pick_button_clicked      (GtkButton      *gtk_button);
 
 
 static void       gimp_pick_button_dispose       (GObject        *object);
@@ -88,7 +88,7 @@ gimp_pick_button_class_init (GimpPickButtonClass* klass)
 
   object_class->dispose = gimp_pick_button_dispose;
 
-  button_class->clicked = gimp_pick_button_clicked;
+  button_class->clicked = _gimp_pick_button_clicked;
 
   klass->color_picked   = NULL;
 }