diff --git a/src/directive/input.js b/src/directive/input.js
index adb8102caf8a..c9553e395424 100644
--- a/src/directive/input.js
+++ b/src/directive/input.js
@@ -560,6 +560,8 @@ function radioInputType(scope, element, attr, ctrl) {
     var value = attr.value;
     element[0].checked = isDefined(value) && (value == ctrl.$viewValue);
   };
+
+  attr.$observe('value', ctrl.$render);
 }
 
 function checkboxInputType(scope, element, attr, ctrl) {
diff --git a/test/directive/inputSpec.js b/test/directive/inputSpec.js
index 22c77f53aaae..0b848df154d2 100644
--- a/test/directive/inputSpec.js
+++ b/test/directive/inputSpec.js
@@ -720,18 +720,30 @@ describe('input', function() {
     });
 
 
-    // TODO(vojta): change interpolate ?
-    xit('should allow {{expr}} as value', function() {
+    it('should allow {{expr}} as value', function() {
       scope.some = 11;
       compileInput(
           '<input type="radio" ng-model="value" value="{{some}}" />' +
           '<input type="radio" ng-model="value" value="{{other}}" />');
 
-      browserTrigger(inputElm[0]);
-      expect(scope.value).toBe(true);
+      scope.$apply(function() {
+        scope.value = 'blue';
+        scope.some = 'blue';
+        scope.other = 'red';
+      });
+
+      expect(inputElm[0].checked).toBe(true);
+      expect(inputElm[1].checked).toBe(false);
 
       browserTrigger(inputElm[1]);
-      expect(scope.value).toBe(false);
+      expect(scope.value).toBe('red');
+
+      scope.$apply(function() {
+        scope.other = 'non-red';
+      });
+
+      expect(inputElm[0].checked).toBe(false);
+      expect(inputElm[1].checked).toBe(false);
     });
   });