diff --git a/src/UrlParams.test.ts b/src/UrlParams.test.ts
index f78ffae4..10f1386b 100644
--- a/src/UrlParams.test.ts
+++ b/src/UrlParams.test.ts
@@ -97,7 +97,11 @@ describe("UrlParams", () => {
     });
 
     it("respected in widget mode", () => {
-      expect(getUrlParams("?preload=true&widgetId=12345").preload).toBe(true);
+      expect(
+        getUrlParams(
+          "?preload=true&widgetId=12345&parentUrl=https%3A%2F%2Flocalhost%2Ffoo",
+        ).preload,
+      ).toBe(true);
     });
   });
 
diff --git a/src/UrlParams.ts b/src/UrlParams.ts
index e471a9d9..216e5b35 100644
--- a/src/UrlParams.ts
+++ b/src/UrlParams.ts
@@ -212,11 +212,12 @@ export const getUrlParams = (
   const fontScale = parseFloat(parser.getParam("fontScale") ?? "");
 
   const widgetId = parser.getParam("widgetId");
-  const isWidget = !!widgetId;
+  const parentUrl = parser.getParam("parentUrl");
+  const isWidget = !!widgetId && !!parentUrl;
 
   return {
     widgetId,
-    parentUrl: parser.getParam("parentUrl"),
+    parentUrl,
 
     // NB. we don't validate roomId here as we do in getRoomIdentifierFromUrl:
     // what would we do if it were invalid? If the widget API says that's what