diff --git a/github.js b/github.js
index f3e504d2..8dc42699 100644
--- a/github.js
+++ b/github.js
@@ -409,14 +409,16 @@
       this.commit = function(parent, tree, message, cb) {
         var data = {
           "message": message,
-          "author": {
-            "name": options.username
-          },
           "parents": [
             parent
           ],
           "tree": tree
         };
+        if(options.username) {
+          data.author = {
+            "name": options.username
+          };
+        }
 
         _request("POST", repoPath + "/git/commits", data, function(err, res) {
           currentTree.sha = res.sha; // update latest commit