diff --git a/clutter/clutter-base-types.c b/clutter/clutter-base-types.c
index 7c4794f0c..91fbd95a1 100644
--- a/clutter/clutter-base-types.c
+++ b/clutter/clutter-base-types.c
@@ -1376,10 +1376,8 @@ clutter_matrix_init_from_array (ClutterMatrix *matrix,
  * Since: 1.12
  */
 ClutterMatrix *
-clutter_matrix_init_from_matrix (ClutterMatrix *a,
-                                 ClutterMatrix *b)
+clutter_matrix_init_from_matrix (ClutterMatrix       *a,
+                                 const ClutterMatrix *b)
 {
-  memcpy (b, a, sizeof (ClutterMatrix));
-
-  return a;
+  return memcpy (a, b, sizeof (ClutterMatrix));
 }
diff --git a/clutter/clutter-types.h b/clutter/clutter-types.h
index 30205686c..d5e4662c2 100644
--- a/clutter/clutter-types.h
+++ b/clutter/clutter-types.h
@@ -697,12 +697,12 @@ void clutter_interval_register_progress_func (GType               value_type,
 GType clutter_matrix_get_type (void) G_GNUC_CONST;
 
 ClutterMatrix * clutter_matrix_alloc            (void);
-ClutterMatrix * clutter_matrix_init_identity    (ClutterMatrix *matrix);
-ClutterMatrix * clutter_matrix_init_from_array  (ClutterMatrix *matrix,
-                                                 const float    values[16]);
-ClutterMatrix * clutter_matrix_init_from_matrix (ClutterMatrix *a,
-                                                 ClutterMatrix *b);
-void            clutter_matrix_free             (ClutterMatrix *matrix);
+ClutterMatrix * clutter_matrix_init_identity    (ClutterMatrix       *matrix);
+ClutterMatrix * clutter_matrix_init_from_array  (ClutterMatrix       *matrix,
+                                                 const float          values[16]);
+ClutterMatrix * clutter_matrix_init_from_matrix (ClutterMatrix       *a,
+                                                 const ClutterMatrix *b);
+void            clutter_matrix_free             (ClutterMatrix       *matrix);
 
 G_END_DECLS