diff --git a/src/dat/controllers/UndefinedController.js b/src/dat/controllers/UndefinedController.js
new file mode 100644
index 0000000..3a15d7f
--- /dev/null
+++ b/src/dat/controllers/UndefinedController.js
@@ -0,0 +1,64 @@
+/**
+ * dat-gui JavaScript Controller Library
+ * http://code.google.com/p/dat-gui
+ *
+ * Copyright 2011 Data Arts Team, Google Creative Lab
+ *
+ * UndefinedController (an adapted StringController) by mikenon
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ */
+
+define([
+  'dat/controllers/Controller',
+  'dat/dom/dom',
+  'dat/utils/common'
+], function (Controller, dom, common) {
+
+  /**
+   * @class Provides a *disabled* text input indicating the value of the property
+   *        is undefined. Calling reset() on the controller will remove and re-add it.
+   *        It is intended to be used as a placeholder, where the gui is built before
+   *        some required variable has been initialized.
+   *
+   * @extends dat.controllers.Controller
+   *
+   * @param {Object} object The object to be manipulated
+   * @param {string} property The name of the property to be manipulated
+   *
+   * @member dat.controllers
+   */
+  var UndefinedController = function (object, property) {
+    UndefinedController.superclass.call(this, object, property);
+
+    var _this = this;
+
+    this.__input = document.createElement('input');
+    this.__input.setAttribute('type', 'text');
+    this.__input.setAttribute('disabled', true);
+    this.domElement.appendChild(this.__input);
+  };
+
+  UndefinedController.superclass = Controller;
+
+  common.extend(
+    UndefinedController.prototype,
+    Controller.prototype, {
+      updateDisplay: function () {
+        if (this.__onFinishChange) {
+          if (!common.isUndefined(this.object[this.property])) {
+            this.__onFinishChange.call(this.object[this.property])
+          }
+        }
+        return UndefinedController.superclass.prototype.updateDisplay.call(this);
+      },
+
+    }
+  );
+
+  return UndefinedController;
+});
diff --git a/src/dat/controllers/factory.js b/src/dat/controllers/factory.js
index 2ce8ecc..87cba83 100644
--- a/src/dat/controllers/factory.js
+++ b/src/dat/controllers/factory.js
@@ -18,9 +18,10 @@ define([
     'dat/controllers/StringController',
     'dat/controllers/FunctionController',
     'dat/controllers/BooleanController',
+    'dat/controllers/UndefinedController',
     'dat/utils/common'
   ],
-  function (OptionController, NumberControllerBox, NumberControllerSlider, StringController, FunctionController, BooleanController, common) {
+  function (OptionController, NumberControllerBox, NumberControllerSlider, StringController, FunctionController, BooleanController, UndefinedController, common) {
 
     return function (object, property) {
 
@@ -63,6 +64,10 @@ define([
         return new BooleanController(object, property);
       }
 
+      if (common.isUndefined(initialValue)) {
+        return new UndefinedController(object, property);
+      }
+
     }
 
   });
diff --git a/src/dat/gui/GUI.js b/src/dat/gui/GUI.js
index c9830c2..0f9463c 100644
--- a/src/dat/gui/GUI.js
+++ b/src/dat/gui/GUI.js
@@ -26,6 +26,7 @@ define([
   'dat/controllers/NumberControllerSlider',
   'dat/controllers/OptionController',
   'dat/controllers/ColorController',
+  'dat/controllers/UndefinedController',
 
   'dat/utils/requestAnimationFrame',
 
@@ -34,7 +35,7 @@ define([
 
   'dat/utils/common'
 
-], function (css, saveDialogueContents, styleSheet, controllerFactory, Controller, BooleanController, FunctionController, NumberControllerBox, NumberControllerSlider, OptionController, ColorController, requestAnimationFrame, CenteredDiv, dom, common) {
+], function (css, saveDialogueContents, styleSheet, controllerFactory, Controller, BooleanController, FunctionController, NumberControllerBox, NumberControllerSlider, OptionController, ColorController, UndefinedController, requestAnimationFrame, CenteredDiv, dom, common) {
 
   css.inject(styleSheet);
 
@@ -814,7 +815,7 @@ define([
 
   function add(gui, object, property, params) {
 
-    if (object[property] === undefined) {
+    if (!common.hasOwnProperty(object, property)) {
       throw new Error("Object " + object + " has no property \"" + property + "\"");
     }
 
@@ -1017,6 +1018,17 @@ define([
 
       controller.updateDisplay();
 
+    } else if (controller instanceof UndefinedController) {
+      controller.__onFinishChange = function (val) {
+        controller.remove();
+        return add(
+          gui,
+          controller.object,
+          controller.property, {
+            before: controller.__li.nextElementSibling
+          }
+        );
+      }
     }
 
     controller.setValue = common.compose(function (r) {
diff --git a/src/dat/gui/style.css b/src/dat/gui/style.css
index da2954f..1728f38 100644
--- a/src/dat/gui/style.css
+++ b/src/dat/gui/style.css
@@ -412,3 +412,11 @@
 .dg .c .slider:hover .slider-fg {
   background: #44abda;
 }
+
+.dg .cr.undefined {
+  border-left: 3px dotted #919191;
+}
+
+.dg .cr.undefined input[type=text] {
+  background: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAJElEQVQIW2OcOHHi//z8fEYGJADmoEvAVSBLoGiDSaAIwowCAAMYEriV4NZdAAAAAElFTkSuQmCC) repeat;
+}
diff --git a/src/dat/utils/common.js b/src/dat/utils/common.js
index 59dc09f..3cdf93a 100644
--- a/src/dat/utils/common.js
+++ b/src/dat/utils/common.js
@@ -132,6 +132,12 @@ define([], function () {
 
     isFunction: function (obj) {
       return Object.prototype.toString.call(obj) === '[object Function]';
+    },
+
+    hasOwnProperty: function (obj, prop) {
+      var proto = obj.__proto__ || obj.constructor.prototype;
+      return (prop in obj) &&
+        (!(prop in proto) || (proto[prop] !== obj[prop]));
     }
 
   };