diff --git a/menu/internal/controllers/surfacePositionController.ts b/menu/internal/controllers/surfacePositionController.ts
index cc9e184f38..584b4b64cf 100644
--- a/menu/internal/controllers/surfacePositionController.ts
+++ b/menu/internal/controllers/surfacePositionController.ts
@@ -7,6 +7,20 @@
 import {ReactiveController, ReactiveControllerHost} from 'lit';
 import {StyleInfo} from 'lit/directives/style-map.js';
 
+/**
+ * Declare popoverAPI functions. See
+ * https://developer.mozilla.org/en-US/docs/Web/API/Popover_API
+ * Without this, closure will rename these functions. Can remove once these
+ * functions make it into the typescript lib.
+ */
+declare global {
+  interface HTMLElement {
+    showPopover(): void;
+    hidePopover(): void;
+    togglePopover(force: boolean): void;
+  }
+}
+
 /**
  * An enum of supported Menu corners
  */