diff --git a/poly/polymorphic.py b/poly/polymorphic.py
index 14781c5..6fcd617 100644
--- a/poly/polymorphic.py
+++ b/poly/polymorphic.py
@@ -938,6 +938,9 @@ class PolymorphicModel(models.Model):
     p_classname = models.CharField(max_length=100, default='')
     p_appname = models.CharField(max_length=50, default='')
 
+    # some applications want to know the name of fields that are added to its models
+    polymorphic_internal_model_fields = [ 'p_classname', 'p_appname' ]
+
     objects = PolymorphicManager()
     base_objects = models.Manager()