diff --git a/when/when.d.ts b/when/when.d.ts
index 2389a4243..dbf4050a0 100644
--- a/when/when.d.ts
+++ b/when/when.d.ts
@@ -51,6 +51,7 @@ declare module When {
         promise: Promise<T>;
         reject(reason: any): void;
         resolve(value?: T): void;
+        resolve(value?: Promise<T>): void;
     }
 
     interface Promise<T> {