diff --git a/types/mosca/index.d.ts b/types/mosca/index.d.ts
index 77fd94e87b..7ed86cbe56 100644
--- a/types/mosca/index.d.ts
+++ b/types/mosca/index.d.ts
@@ -47,8 +47,7 @@ export class Client {
 
     constructor(connection: any, server: Server);
 
-    close(callback: () => void, reason: string): void;
-    close(reason: string): void;
+    close(callback?: () => void, reason?: string): void;
 }
 
 export class Stats {