diff --git a/node-git/node-git.d.ts b/node-git/node-git.d.ts
index 7e29b0ffd5..f10d217cba 100644
--- a/node-git/node-git.d.ts
+++ b/node-git/node-git.d.ts
@@ -46,9 +46,9 @@ declare module "git" {
         // not implemented!
         clone(options:any, originalPath:any, targetPath:any, callback:Function):void;
 
-        diff(commit1:any, commit2:any, callback:Function):void;
+        diff(commit1:any, commit2:any, callback: (error: any, patch: string) => void):void;
 
-        diff(commit1:any, commit2:any, options:any, callback:Function):void;
+		diff(commit1: any, commit2: any, options: any, callback: (error: any, patch: string) => void):void;
 
         fs_exist(path:any, callback:Function):void;
 
@@ -488,11 +488,11 @@ declare module "git" {
         fork_bare(path:any, options:any, callback:Function):void;
 
         // buggy?
-        diff(a:string, callback:Function):void;
+		diff(a: string, callback: (error: any, patch: string) => void):void;
 
-        diff(a:string, b:string, callback:Function):void;
+		diff(a: string, b: string, callback: (error: any, patch: string) => void):void;
 
-        diff(a:string, b:string, paths:any, callback:Function):void;
+		diff(a: string, b: string, paths: any, callback: (error: any, patch: string) => void):void;
 
         commit_diff(commit:string, callback:Function):void;