diff --git a/src/hb-null.hh b/src/hb-null.hh
index 151277ca7..a3f0ea079 100644
--- a/src/hb-null.hh
+++ b/src/hb-null.hh
@@ -120,8 +120,10 @@ struct hb_nonnull_ptr_t
   inline const T & operator * (void) const { return *get (); }
   inline T ** operator & (void) { return &v; }
   inline const T ** operator & (void) const { return &v; }
-  inline operator T * (void) { return get (); }
-  inline operator const T * (void) const { return get (); }
+  template <typename C>
+  inline operator C * (void) { return get (); }
+  template <typename C>
+  inline operator const C * (void) const { return get (); }
   inline T * get (void) { return v ? v : const_cast<T *> (&Null(T)); }
   inline const T * get (void) const { return v ? v : const_cast<T *> (&Null(T)); }
   inline T * get_raw (void) { return v; }