diff --git a/js/controller.js b/js/controller.js
index 0e22a6d23..cbcca4b37 100644
--- a/js/controller.js
+++ b/js/controller.js
@@ -291,7 +291,7 @@ OO.plugin("Html5Skin", function (OO, _, $, W) {
       this.cleanUpEventListeners()
       this.mb = null;
     },
-    
+
     cleanUpEventListeners : function() {
       this.accessibilityControls.cleanUp()
     },
@@ -345,11 +345,9 @@ OO.plugin("Html5Skin", function (OO, _, $, W) {
 
     onAttributesFetched: function (event, attributes) {
       this.state.attributes = attributes;
-      //anamorphic videos
-      var isAnamorphic = Utils.getPropertyValue(this.state.attributes, 'provider.ots_stretch_to_output');
-      if (isAnamorphic == true || isAnamorphic == "true") {
-        this.state.mainVideoInnerWrapper.addClass('oo-anamorphic');
-      }
+      // This is the first point at which we know whether the video is anamorphic or not,
+      // apply fix if necessary
+      this.trySetAnamorphicFixState(true);
     },
 
     onThumbnailsFetched: function (event, thumbnails) {
@@ -678,12 +676,16 @@ OO.plugin("Html5Skin", function (OO, _, $, W) {
       this.state.isPlayingAd = false;
       this.state.pluginsElement.removeClass("oo-showing");
       this.state.pluginsClickElement.removeClass("oo-showing");
+      // Restore anamorphic videos fix after ad playback if necessary
+      this.trySetAnamorphicFixState(true);
       this.renderSkin();
     },
 
     onWillPlayAds: function(event) {
       OO.log("onWillPlayAds is called from event = " + event);
       this.state.isPlayingAd = true;
+      // Anamorphic videos fix should not be active during ad playback
+      this.trySetAnamorphicFixState(false);
       this.state.pluginsElement.addClass("oo-showing");
       this.state.pluginsElement.css({
         height: "",
@@ -1472,6 +1474,32 @@ OO.plugin("Html5Skin", function (OO, _, $, W) {
       this.mb.publish(OO.EVENTS.SAVE_PLAYER_SETTINGS, this.state.persistentSettings);
     },
 
+    /**
+     * Used to enable or disable the CSS workaround that prevents anamorphic videos from
+     * being distorted on Firefox. The fix will only be enabled if ots_stretch_to_output
+     * is set to true in the player attributes.
+     * Note that currently the oo-anamorphic class has effect only on Firefox.
+     * @param {boolen} enabled A value that determines whether to enable or disable the anamorphic videos CSS fix.
+     */
+    trySetAnamorphicFixState: function(enabled) {
+      if (!this.state || !this.state.mainVideoInnerWrapper) {
+        return;
+      }
+
+      if (enabled) {
+        var isAnamorphic = Utils.getPropertyValue(this.state.attributes, 'provider.ots_stretch_to_output');
+
+        // Only enable anamorphic videos fix if video actually requires it
+        if (isAnamorphic === true || isAnamorphic === 'true') {
+          this.state.mainVideoInnerWrapper.addClass('oo-anamorphic');
+          OO.log('Anamorphic video fix: ON');
+        }
+      } else {
+        this.state.mainVideoInnerWrapper.removeClass('oo-anamorphic');
+        OO.log('Anamorphic video fix: OFF');
+      }
+    },
+
     toggleClosedCaptionEnabled: function() {
       this.state.closedCaptionOptions.enabled = !this.state.closedCaptionOptions.enabled;
       this.state.persistentSettings.closedCaptionOptions['enabled'] = !!this.state.closedCaptionOptions.enabled;
diff --git a/package.json b/package.json
index 9a0d50735..8f9d17320 100644
--- a/package.json
+++ b/package.json
@@ -51,6 +51,7 @@
     "react-addons-test-utils": "0.14.7",
     "react-tools": "*",
     "reactify": "1.1.1",
+    "sinon": "^2.1.0",
     "underscore": "1.3.3",
     "vinyl-buffer": "^1.0.0",
     "vinyl-source-stream": "^1.0.0",
diff --git a/tests/controller-test.js b/tests/controller-test.js
index 849a29301..6bd06477b 100644
--- a/tests/controller-test.js
+++ b/tests/controller-test.js
@@ -8,6 +8,7 @@ jest.dontMock('underscore');
 jest.dontMock('jquery');
 
 var CONSTANTS = require('../js/constants/constants');
+var sinon = require('sinon');
 
 /**
  * Mock OO
@@ -197,6 +198,7 @@ OO = {
       displayMoreOptionsScreen: function(a) {},
       closeMoreOptionsScreen: function() {},
       pausedCallback: function() {},
+      trySetAnamorphicFixState: function() {},
       renderSkin: function() {window.isSkinRendered = true;},
       cancelTimer: function() {window.isTimerCanceled = true;},
       startHideControlBarTimer: function() {},
@@ -577,6 +579,57 @@ OO = {
       });
     });
 
+    describe('Controller testing Anamorphic videos fix', function() {
+      var addClassSpy = null;
+      var removeClassSpy = null;
+      var attributesParam = null;
+      var attributesState = JSON.parse(JSON.stringify(controllerMock.state.attributes));
+
+      beforeEach(function() {
+        attributesParam = {
+          provider: {
+            'ots_stretch_to_output': true
+          }
+        };
+        addClassSpy = sinon.spy(controllerMock.state.mainVideoInnerWrapper, 'addClass');
+        removeClassSpy = sinon.spy(controllerMock.state.mainVideoInnerWrapper, 'removeClass');
+      });
+
+      afterEach(function() {
+        controllerMock.state.mainVideoInnerWrapper.addClass.restore();
+        controllerMock.state.mainVideoInnerWrapper.removeClass.restore();
+        controllerMock.state.attributes = attributesState;
+      });
+
+      it('should apply anamorphic CSS fix when ots_stretch_to_output is true', function() {
+        Html5Skin.onAttributesFetched.call(controllerMock, 'customerUi', attributesParam);
+        Html5Skin.trySetAnamorphicFixState.call(controllerMock, true);
+        expect(addClassSpy.callCount).toBe(1);
+        expect(removeClassSpy.callCount).toBe(0);
+      });
+
+      it('should not apply anamorphic CSS fix when ots_stretch_to_output isn\'t true', function() {
+        attributesParam.provider = {};
+        Html5Skin.onAttributesFetched.call(controllerMock, 'customerUi', attributesParam);
+        Html5Skin.trySetAnamorphicFixState.call(controllerMock, true);
+        attributesParam.provider = { 'ots_stretch_to_output': false };
+        Html5Skin.onAttributesFetched.call(controllerMock, 'customerUi', attributesParam);
+        Html5Skin.trySetAnamorphicFixState.call(controllerMock, true);
+        expect(addClassSpy.callCount).toBe(0);
+        expect(removeClassSpy.callCount).toBe(0);
+      });
+
+      it('should disable anamorphic CSS fix when passing false', function() {
+        Html5Skin.onAttributesFetched.call(controllerMock, 'customerUi', attributesParam);
+        Html5Skin.trySetAnamorphicFixState.call(controllerMock, true);
+        expect(addClassSpy.callCount).toBe(1);
+        Html5Skin.onWillPlayAds.call(controllerMock, 'customerUi');
+        Html5Skin.trySetAnamorphicFixState.call(controllerMock, false);
+        expect(addClassSpy.callCount).toBe(1);
+        expect(removeClassSpy.callCount).toBe(1);
+      });
+    });
+
     //test destroy functions last
     Html5Skin.onEmbedCodeChanged.call(controllerMock, 'customerUi', 'RmZW4zcDo6KqkTIhn1LnowEZyUYn5Tb2', {});
     Html5Skin.onAssetChanged.call(controllerMock, 'customerUi', {content: {streams: [{is_live_stream: true}], title: 'Title', posterImages: [{url:'www.ooyala.com'}]}});