diff --git a/include/wx/mac/corefoundation/cfstring.h b/include/wx/mac/corefoundation/cfstring.h
index 4887956206..c1d8c1a809 100644
--- a/include/wx/mac/corefoundation/cfstring.h
+++ b/include/wx/mac/corefoundation/cfstring.h
@@ -74,6 +74,8 @@ public:
         m_cfs = NULL ;
     }
 
+    void Assign(CFStringRef ref , bool release = true);
+
     void Assign(const wxString &str,
                 wxFontEncoding encoding = wxFONTENCODING_DEFAULT);