diff --git a/socket.io/socket.io.d.ts b/socket.io/socket.io.d.ts
index ac5381f09f..3f3c042fe1 100644
--- a/socket.io/socket.io.d.ts
+++ b/socket.io/socket.io.d.ts
@@ -91,5 +91,6 @@ declare module SocketIO {
     interface Client {
         conn: any;
         request: any;
+        id: string;
     }
 }