diff --git a/types/mongoose/index.d.ts b/types/mongoose/index.d.ts
index e51290b451..7b02fb96d6 100644
--- a/types/mongoose/index.d.ts
+++ b/types/mongoose/index.d.ts
@@ -2423,6 +2423,13 @@ declare module "mongoose" {
          */
         discriminator<U extends Document>(name: string, schema: Schema): Model<U>;
 
+        /**
+         * Adds a discriminator type.
+         * @param name discriminator model name
+         * @param schema discriminator model schema
+         */
+        discriminator<U extends Document, M extends Model<U>>(name: string, schema: Schema): M;
+
       }
 
       /*