diff --git a/js/ui/unlockDialog.js b/js/ui/unlockDialog.js
index f741b20a6..82a912e51 100644
--- a/js/ui/unlockDialog.js
+++ b/js/ui/unlockDialog.js
@@ -534,6 +534,9 @@ export const UnlockDialog = GObject.registerClass({
         tapAction.connect('tap', this._showPrompt.bind(this));
         this.add_action(tapAction);
 
+        global.backend.connectObject('lid-is-closed-changed',
+            this._showPrompt.bind(this), this);
+
         // Background
         this._backgroundGroup = new Clutter.Actor();
         this.add_child(this._backgroundGroup);