diff --git a/Userland/Libraries/LibWeb/HTML/Window.cpp b/Userland/Libraries/LibWeb/HTML/Window.cpp
index fb5efb24c7..0142ae02d1 100644
--- a/Userland/Libraries/LibWeb/HTML/Window.cpp
+++ b/Userland/Libraries/LibWeb/HTML/Window.cpp
@@ -430,12 +430,6 @@ WebIDL::ExceptionOr<JS::GCPtr<HTML::WindowProxy>> Window::open_impl(StringView u
     return target_browsing_context->window_proxy();
 }
 
-void Window::alert_impl(DeprecatedString const& message)
-{
-    if (auto* page = this->page())
-        page->did_request_alert(message);
-}
-
 bool Window::confirm_impl(DeprecatedString const& message)
 {
     if (auto* page = this->page())
@@ -1142,7 +1136,6 @@ WebIDL::ExceptionOr<void> Window::initialize_web_interfaces(Badge<WindowEnvironm
     define_native_accessor(realm, "devicePixelRatio", device_pixel_ratio_getter, {}, JS::Attribute::Enumerable | JS::Attribute::Configurable);
     u8 attr = JS::Attribute::Writable | JS::Attribute::Enumerable | JS::Attribute::Configurable;
     define_native_function(realm, "open", open, 0, attr);
-    define_native_function(realm, "alert", alert, 0, attr);
     define_native_function(realm, "confirm", confirm, 0, attr);
     define_native_function(realm, "prompt", prompt, 0, attr);
     define_native_function(realm, "setInterval", set_interval, 1, attr);
@@ -1245,6 +1238,18 @@ static JS::ThrowCompletionOr<HTML::Window*> impl_from(JS::VM& vm)
     return vm.throw_completion<JS::TypeError>(JS::ErrorType::NotAnObjectOfType, "Window");
 }
 
+// https://html.spec.whatwg.org/multipage/timers-and-user-prompts.html#dom-alert
+void Window::alert(String const& message)
+{
+    // https://html.spec.whatwg.org/multipage/timers-and-user-prompts.html#simple-dialogs
+    // Note: This method is defined using two overloads, instead of using an optional argument,
+    //       for historical reasons. The practical impact of this is that alert(undefined) is
+    //       treated as alert("undefined"), but alert() is treated as alert("").
+    // FIXME: Make this fully spec compliant.
+    if (auto* page = this->page())
+        page->did_request_alert(message.to_deprecated_string());
+}
+
 JS_DEFINE_NATIVE_FUNCTION(Window::open)
 {
     auto* impl = TRY(impl_from(vm));
@@ -1267,20 +1272,6 @@ JS_DEFINE_NATIVE_FUNCTION(Window::open)
     return TRY(Bindings::throw_dom_exception_if_needed(vm, [&] { return impl->open_impl(url, target, features); }));
 }
 
-JS_DEFINE_NATIVE_FUNCTION(Window::alert)
-{
-    // https://html.spec.whatwg.org/multipage/timers-and-user-prompts.html#simple-dialogs
-    // Note: This method is defined using two overloads, instead of using an optional argument,
-    //       for historical reasons. The practical impact of this is that alert(undefined) is
-    //       treated as alert("undefined"), but alert() is treated as alert("").
-    auto* impl = TRY(impl_from(vm));
-    DeprecatedString message = "";
-    if (vm.argument_count())
-        message = TRY(vm.argument(0).to_deprecated_string(vm));
-    impl->alert_impl(message);
-    return JS::js_undefined();
-}
-
 JS_DEFINE_NATIVE_FUNCTION(Window::confirm)
 {
     auto* impl = TRY(impl_from(vm));
diff --git a/Userland/Libraries/LibWeb/HTML/Window.h b/Userland/Libraries/LibWeb/HTML/Window.h
index 75df91f6c8..40b5c498f6 100644
--- a/Userland/Libraries/LibWeb/HTML/Window.h
+++ b/Userland/Libraries/LibWeb/HTML/Window.h
@@ -66,7 +66,6 @@ public:
     void set_import_maps_allowed(bool import_maps_allowed) { m_import_maps_allowed = import_maps_allowed; }
 
     WebIDL::ExceptionOr<JS::GCPtr<HTML::WindowProxy>> open_impl(StringView url, StringView target, StringView features);
-    void alert_impl(DeprecatedString const&);
     bool confirm_impl(DeprecatedString const&);
     DeprecatedString prompt_impl(DeprecatedString const&, DeprecatedString const&);
     i32 request_animation_frame_impl(WebIDL::CallbackType& js_callback);
@@ -143,6 +142,9 @@ public:
     Vector<JS::NonnullGCPtr<Plugin>> pdf_viewer_plugin_objects();
     Vector<JS::NonnullGCPtr<MimeType>> pdf_viewer_mime_type_objects();
 
+    // JS API functions
+    void alert(String const& message = {});
+
 private:
     explicit Window(JS::Realm&);
 
@@ -265,7 +267,6 @@ private:
     JS_DECLARE_NATIVE_FUNCTION(is_secure_context_getter);
 
     JS_DECLARE_NATIVE_FUNCTION(open);
-    JS_DECLARE_NATIVE_FUNCTION(alert);
     JS_DECLARE_NATIVE_FUNCTION(confirm);
     JS_DECLARE_NATIVE_FUNCTION(prompt);
     JS_DECLARE_NATIVE_FUNCTION(set_interval);
diff --git a/Userland/Libraries/LibWeb/HTML/Window.idl b/Userland/Libraries/LibWeb/HTML/Window.idl
index 19e5f269f7..67bc7da2f4 100644
--- a/Userland/Libraries/LibWeb/HTML/Window.idl
+++ b/Userland/Libraries/LibWeb/HTML/Window.idl
@@ -2,8 +2,11 @@
 #import <DOM/EventTarget.idl>
 
 // https://html.spec.whatwg.org/multipage/nav-history-apis.html#window
-[Global=Window, Exposed=Window, LegacyUnenumerableNamedProperties]
+[Global=Window, Exposed=Window, LegacyUnenumerableNamedProperties, UseNewAKString]
 interface Window : EventTarget {
+    // user prompts
+    undefined alert();
+    undefined alert(DOMString message);
 };
 Window includes GlobalEventHandlers;
 Window includes WindowEventHandlers;