diff --git a/mongodb-legacy.d.ts b/mongodb-legacy.d.ts
index b04fb12..32817c7 100644
--- a/mongodb-legacy.d.ts
+++ b/mongodb-legacy.d.ts
@@ -263,7 +263,10 @@ declare class LegacyCollection<TSchema extends Document = Document> extends Coll
    * @param options - Optional settings for the command
    * @param callback - An optional callback, a Promise will be returned if none is provided
    */
-  insertOne(doc: OptionalUnlessRequiredId<TSchema>, options?: InsertOneOptions): Promise<InsertOneResult<TSchema>>;
+  insertOne(doc: OptionalUnlessRequiredId<TSchema>): Promise<InsertOneResult<TSchema>>;
+  insertOne(doc: OptionalUnlessRequiredId<TSchema>, callback: Callback<InsertOneResult<TSchema>>): void;
+  insertOne(doc: OptionalUnlessRequiredId<TSchema>, options: InsertOneOptions): Promise<InsertOneResult<TSchema>>;
+  insertOne(doc: OptionalUnlessRequiredId<TSchema>, options: InsertOneOptions, callback: Callback<InsertOneResult<TSchema>>): void;
   /**
    * Inserts an array of documents into MongoDB. If documents passed in do not contain the **_id** field,
    * one will be added to each of the documents missing it by the driver, mutating the document. This behavior