diff --git a/dom/url/URL.h b/dom/url/URL.h
index 9d40ca9cf03c..9080bca79471 100644
--- a/dom/url/URL.h
+++ b/dom/url/URL.h
@@ -151,6 +151,12 @@ public:
     GetHref(aRetval, aRv);
   }
 
+  void
+  ToJSON(nsAString& aResult, ErrorResult& aRv) const
+  {
+    GetHref(aResult, aRv);
+  }
+
   // URLSearchParamsObserver
   void
   URLSearchParamsUpdated(URLSearchParams* aSearchParams) override;
diff --git a/dom/url/tests/test_url.html b/dom/url/tests/test_url.html
index 533a79f402ec..73e75667d8db 100644
--- a/dom/url/tests/test_url.html
+++ b/dom/url/tests/test_url.html
@@ -450,5 +450,11 @@
     url = new URL("data:text/html,<a href=\"http://example.org/?q\">Link</a>");
     is(url.href, "data:text/html,<a%20href=\"http://example.org/?q\">Link</a>");
   </script>
+
+  <script>
+    var u = new URL('http://www.example.org');
+    ok(u.toJSON(), 'http://www.example.org', "URL.toJSON()");
+    is(JSON.stringify(u), "\"http://www.example.org/\"", "JSON.stringify(u) works");
+  </script>
 </body>
 </html>
diff --git a/dom/webidl/URL.webidl b/dom/webidl/URL.webidl
index 53a6fa7aa3f9..bab0864dff79 100644
--- a/dom/webidl/URL.webidl
+++ b/dom/webidl/URL.webidl
@@ -44,9 +44,12 @@ interface URL {
            attribute USVString pathname;
   [Throws]
            attribute USVString search;
-  readonly attribute URLSearchParams searchParams;
+  [SameObject] readonly attribute URLSearchParams searchParams;
   [Throws]
            attribute USVString hash;
+
+  [Throws]
+  USVString toJSON();
 };
 
 partial interface URL {