diff --git a/lib/aggregate.js b/lib/aggregate.js
index 3704869f748..d38fa91dbc6 100644
--- a/lib/aggregate.js
+++ b/lib/aggregate.js
@@ -39,7 +39,7 @@ const readConcern = Query.prototype.readConcern;
  * ```javascript
  *   new Aggregate([{ $match: { _id: '00000000000000000000000a' } }]);
  *   // Do this instead to cast to an ObjectId
- *   new Aggregate([{ $match: { _id: mongoose.Types.ObjectId('00000000000000000000000a') } }]);
+ *   new Aggregate([{ $match: { _id: new mongoose.Types.ObjectId('00000000000000000000000a') } }]);
  * ```
  *
  * @see MongoDB http://docs.mongodb.org/manual/applications/aggregation/