diff --git a/lib/relation-definition.js b/lib/relation-definition.js
index 220b18a8..50320f6b 100644
--- a/lib/relation-definition.js
+++ b/lib/relation-definition.js
@@ -918,6 +918,7 @@ HasManyThrough.prototype.create = function create(data, done) {
 /**
  * Add the target model instance to the 'hasMany' relation
  * @param {Object|ID} acInst The actual instance or id value
+ * @param {Object} [data] Optional data object for the through model to be created
  */
 HasManyThrough.prototype.add = function (acInst, data, done) {
   var self = this;
@@ -2553,12 +2554,17 @@ ReferencesMany.prototype.build = function(targetModelData) {
  * Add the target model instance to the 'embedsMany' relation
  * @param {Object|ID} acInst The actual instance or id value
  */
-ReferencesMany.prototype.add = function (acInst, cb) {
+ReferencesMany.prototype.add = function (acInst, data, cb) {
   var self = this;
   var definition = this.definition;
   var modelTo = this.definition.modelTo;
   var modelInstance = this.modelInstance;
   
+  if (typeof data === 'function') {
+    cb = data;
+    data = {};
+  }
+
   var pk = this.definition.keyTo;
   var fk = this.definition.keyFrom;