diff --git a/types/mongoose/index.d.ts b/types/mongoose/index.d.ts
index da4714d59f..122de69b7f 100644
--- a/types/mongoose/index.d.ts
+++ b/types/mongoose/index.d.ts
@@ -2435,9 +2435,8 @@ declare module "mongoose" {
      * If a callback is not passed, the aggregate itself is returned.
      * @param aggregations pipeline operator(s) or operator array
      */
-    aggregate(): Aggregate<any[]>;
-    aggregate(aggregations: any[]): Aggregate<any[]>;
-    aggregate(aggregations: any[], cb: Function): Promise<any[]>;
+    aggregate(aggregations?: any[]): Aggregate<any[]>;
+    aggregate(aggregations: any[], cb?: Function): Promise<any[]>;
 
     /** Counts number of matching documents in a database collection. */
     count(conditions: any, callback?: (err: any, count: number) => void): Query<number>;