diff --git a/types/ember/index.d.ts b/types/ember/index.d.ts
index 8a47f00476..a89d6bcc6f 100755
--- a/types/ember/index.d.ts
+++ b/types/ember/index.d.ts
@@ -1182,7 +1182,7 @@ declare module 'ember' {
              * argument for all items in the enumerable. This method is often simpler/faster
              * than using a callback.
              */
-            isEvery(key: string, value: any): boolean;
+            isEvery(key: string, value?: any): boolean;
             /**
              * Returns `true` if the passed function returns true for any item in the
              * enumeration.
diff --git a/types/ember/test/ember-tests.ts b/types/ember/test/ember-tests.ts
index f0aff2478c..c049512eb0 100755
--- a/types/ember/test/ember-tests.ts
+++ b/types/ember/test/ember-tests.ts
@@ -130,6 +130,7 @@ const isHappy = (person: typeof Person3.prototype): boolean => {
 };
 people2.every(isHappy);
 people2.any(isHappy);
+people2.isEvery('isHappy');
 people2.isEvery('isHappy', true);
 people2.isAny('isHappy', 'true');
 people2.isAny('isHappy');