1 files changed, 11 insertions, 3 deletions
diff --git a/lib/email.js b/lib/email.js
index c369530..902dd46 100644
--- a/lib/email.js
+++ b/lib/email.js
@@ -52,9 +52,17 @@ function Email(params) {
   }
 }
 
-Email.prototype.addHeader = function(object_literal) {
-  if (_.isObject(object_literal)) {
-    _.extend(this.headers, object_literal);
+Email.prototype.addHeader = function(object_literal_or_key, value) {
+  if (typeof value === "undefined" || value === null) { 
+    value = ""; 
+  }
+
+  if (_.isObject(object_literal_or_key)) {
+    _.extend(this.headers, object_literal_or_key);
+  } else {
+    var object_to_add = {}
+    object_to_add[object_literal_or_key] = value;
+    _.extend(this.headers, object_to_add);
   }
 };