diff --git a/src/fake.ts b/src/fake.ts
index fbdfcad1c4e..e435ce8966e 100644
--- a/src/fake.ts
+++ b/src/fake.ts
@@ -31,7 +31,7 @@ export class Fake {
    * @method faker.fake
    * @param str
    */
-  fake(str: string) {
+  fake(str: string): string {
     // setup default response as empty string
     let res = '';