diff --git a/docs/reference/gtk/gtk3-sections.txt b/docs/reference/gtk/gtk3-sections.txt
index 956d52b5ee..32d0fad15d 100644
--- a/docs/reference/gtk/gtk3-sections.txt
+++ b/docs/reference/gtk/gtk3-sections.txt
@@ -5727,6 +5727,7 @@ GTK_THEMING_ENGINE_GET_CLASS
 GTK_IS_THEMING_ENGINE
 GTK_IS_THEMING_ENGINE_CLASS
 <SUBSECTION Private>
+GtkThemingEnginePrivate
 GTK_TYPE_THEMING_ENGINE
 gtk_theming_engine_get_type
 </SECTION>
diff --git a/gtk/gtkthemingengine.c b/gtk/gtkthemingengine.c
index 64a2bc5bdd..1e5d735d64 100644
--- a/gtk/gtkthemingengine.c
+++ b/gtk/gtkthemingengine.c
@@ -55,8 +55,6 @@
  * style information contained in the rendered object's #GtkStyleContext.
  */
 
-typedef struct GtkThemingEnginePrivate GtkThemingEnginePrivate;
-
 enum {
   SIDE_LEFT   = 1,
   SIDE_BOTTOM = 1 << 1,
diff --git a/gtk/gtkthemingengine.h b/gtk/gtkthemingengine.h
index 63c792c1fd..d19d6d3b7f 100644
--- a/gtk/gtkthemingengine.h
+++ b/gtk/gtkthemingengine.h
@@ -41,12 +41,13 @@ G_BEGIN_DECLS
 #define GTK_THEMING_ENGINE_GET_CLASS(o) (G_TYPE_INSTANCE_GET_CLASS  ((o), GTK_TYPE_THEMING_ENGINE, GtkThemingEngineClass))
 
 typedef struct _GtkThemingEngine GtkThemingEngine;
+typedef struct GtkThemingEnginePrivate GtkThemingEnginePrivate;
 typedef struct _GtkThemingEngineClass GtkThemingEngineClass;
 
 struct _GtkThemingEngine
 {
   GObject parent_object;
-  gpointer priv;
+  GtkThemingEnginePrivate *priv;
 };
 
 /**