diff --git a/src/operator/finally.ts b/src/operator/finally.ts
index 3628cec781..9b59243342 100644
--- a/src/operator/finally.ts
+++ b/src/operator/finally.ts
@@ -16,7 +16,7 @@ export function _finally<T>(callback: () => void): Observable<T> {
 }
 
 export interface FinallySignature<T> {
-  <T>(callback: () => void): Observable<T>;
+  (callback: () => void): Observable<T>;
 }
 
 class FinallyOperator<T> implements Operator<T, T> {