diff --git a/rest_framework/fields.py b/rest_framework/fields.py
index 75ce1b9f9..da588082c 100644
--- a/rest_framework/fields.py
+++ b/rest_framework/fields.py
@@ -581,7 +581,7 @@ class HyperlinkedRelatedField(RelatedField):
         except:
             pass
 
-        raise ValidationError('Could not resolve URL for field using view name "%s"', view_name)
+        raise ValidationError('Could not resolve URL for field using view name "%s"' % view_name)
 
     def from_native(self, value):
         # Convert URL -> model instance pk
@@ -680,7 +680,7 @@ class HyperlinkedIdentityField(Field):
         except:
             pass
 
-        raise ValidationError('Could not resolve URL for field using view name "%s"', view_name)
+        raise ValidationError('Could not resolve URL for field using view name "%s"' % view_name)
 
 
 ##### Typed Fields #####