diff --git a/types/p-defer/index.d.ts b/types/p-defer/index.d.ts
index 54ba6dd98b..7eff607e7d 100644
--- a/types/p-defer/index.d.ts
+++ b/types/p-defer/index.d.ts
@@ -5,7 +5,7 @@
 
 declare namespace pDefer {
 	interface DeferredPromise<T> {
-		resolve<U>(value: U | PromiseLike<U>): Promise<U>;
+		resolve<U>(value?: U | PromiseLike<U>): Promise<U>;
 		reject(reason: any): Promise<never>;
 		promise: Promise<T>;
 	}