diff --git a/rest_framework/fields.py b/rest_framework/fields.py
index a4e29a30a..4c2064261 100644
--- a/rest_framework/fields.py
+++ b/rest_framework/fields.py
@@ -522,7 +522,10 @@ class HyperlinkedRelatedField(RelatedField):
         view_name = self.view_name
         request = self.context.get('request', None)
         format = self.format or self.context.get('format', None)
-        kwargs = {self.pk_url_kwarg: obj.pk}
+        pk = getattr(obj, 'pk', None)
+        if pk is None:
+            return
+        kwargs = {self.pk_url_kwarg: pk}
         try:
             return reverse(view_name, kwargs=kwargs, request=request, format=format)
         except:
diff --git a/rest_framework/tests/hyperlinkedserializers.py b/rest_framework/tests/hyperlinkedserializers.py
index 3a955ddfb..5ab850afa 100644
--- a/rest_framework/tests/hyperlinkedserializers.py
+++ b/rest_framework/tests/hyperlinkedserializers.py
@@ -224,11 +224,12 @@ class TestOptionalRelationHyperlinkedView(TestCase):
 
     def setUp(self):
         """
-        Create 1 OptionaRelationModel intances.
+        Create 1 OptionalRelationModel intances.
         """
         OptionalRelationModel().save()
         self.objects = OptionalRelationModel.objects
         self.detail_view = OptionalRelationDetail.as_view()
+        self.data = {"url": "http://testserver/optionalrelation/1/", "other": None}
 
     def test_get_detail_view(self):
         """
@@ -238,5 +239,4 @@ class TestOptionalRelationHyperlinkedView(TestCase):
         request = factory.get('/optionalrelationmodel-detail/1')
         response = self.detail_view(request, pk=1).render()
         self.assertEquals(response.status_code, status.HTTP_200_OK)
-
-
+        self.assertEquals(response.data, self.data)