diff --git a/types/winrt-uwp/index.d.ts b/types/winrt-uwp/index.d.ts
index 2e1eb9391d..6e0a460e33 100644
--- a/types/winrt-uwp/index.d.ts
+++ b/types/winrt-uwp/index.d.ts
@@ -20,7 +20,7 @@ declare namespace Windows {
 }
 
 declare namespace Windows.Foundation {
-    interface IPromise<TResult> {
+    interface IPromise<TResult> extends PromiseLike<TResult> {
         then<U>(success?: (value: TResult) => IPromise<U>, error?: (error: any) => IPromise<U>, progress?: (progress: any) => void): IPromise<U>;
         then<U>(success?: (value: TResult) => IPromise<U>, error?: (error: any) => U, progress?: (progress: any) => void): IPromise<U>;
         then<U>(success?: (value: TResult) => U, error?: (error: any) => IPromise<U>, progress?: (progress: any) => void): IPromise<U>;