diff --git a/src/lib/es5.d.ts b/src/lib/es5.d.ts
index 2c457a432c6b8..1252335ea2d5b 100644
--- a/src/lib/es5.d.ts
+++ b/src/lib/es5.d.ts
@@ -210,6 +210,8 @@ interface ObjectConstructor {
       * Returns the names of the enumerable properties and methods of an object.
       * @param o Object that contains the properties and methods. This can be an object that you created or an existing Document Object Model (DOM) object.
       */
+    keys<T>(o: Array<T>): string[];
+    keys<T extends { [key: string]: any }>(o: T): (keyof T & string)[];
     keys(o: any): string[];
 }