diff --git a/js/src/xpconnect/src/XPCNativeWrapper.cpp b/js/src/xpconnect/src/XPCNativeWrapper.cpp
index b22d6c455ff8..665af7e7cc45 100644
--- a/js/src/xpconnect/src/XPCNativeWrapper.cpp
+++ b/js/src/xpconnect/src/XPCNativeWrapper.cpp
@@ -645,8 +645,20 @@ XPC_NW_NewResolve(JSContext *cx, JSObject *obj, jsval id, uintN flags,
 
   if (id == GetRTStringByIndex(cx, XPCJSRuntime::IDX_TO_STRING)) {
     *objp = obj;
-    return JS_DefineFunction(cx, obj, "toString",
-                             XPC_NW_toString, 0, 0) != nsnull;
+
+    // See the comment in XPC_NW_WrapFunction for why we create this function
+    // like this.
+    JSFunction *fun = JS_NewFunction(cx, XPC_NW_toString, 0, 0, nsnull,
+                                     "toString");
+    if (!fun) {
+      return JS_FALSE;
+    }
+
+    JSObject *funobj = JS_GetFunctionObject(fun);
+    STOBJ_SET_PARENT(funobj, obj);
+
+    return JS_DefineProperty(cx, obj, "toString", OBJECT_TO_JSVAL(funobj),
+                             nsnull, nsnull, 0);
   }
 
   if (!EnsureLegalActivity(cx, obj)) {