diff --git a/express/express.d.ts b/express/express.d.ts
index 268598358..9cd6e4596 100644
--- a/express/express.d.ts
+++ b/express/express.d.ts
@@ -63,7 +63,7 @@ declare module "express" {
         }
 
         export class Router {
-          new (options: any): Router;
+          new (options?: any): Router;
 
           middleware (): any;