diff --git a/jest/jest.d.ts b/jest/jest.d.ts
index d500525b63..2ee7657283 100644
--- a/jest/jest.d.ts
+++ b/jest/jest.d.ts
@@ -40,6 +40,7 @@ declare module jest {
         toBeFalsy(): boolean;
         toBeTruthy(): boolean;
         toBeNull(): boolean;
+        toBeDefined(): boolean;
         toBeUndefined(): boolean;
         toMatch(expected: RegExp): boolean;
         toContain(expected: string): boolean;