diff --git a/extras_mongoengine/fields.py b/extras_mongoengine/fields.py
index 5871ddf..67c2f7a 100644
--- a/extras_mongoengine/fields.py
+++ b/extras_mongoengine/fields.py
@@ -75,7 +75,8 @@ class EnumField(object):
 
     def __init__(self, enum, *args, **kwargs):
         self.enum = enum
-        kwargs['choices'] = [choice for choice in enum]
+        if 'choices' not in kwargs:
+            kwargs['choices'] = [(c.value, c.name) for c in enum]
         super(EnumField, self).__init__(*args, **kwargs)
 
     def __get_value(self, enum):
@@ -96,7 +97,7 @@ def validate(self, value):
 
     def _validate(self, value, **kwargs):
         return super(EnumField, self)._validate(
-                self.enum(self.__get_value(value)), **kwargs)
+                self.__get_value(value), **kwargs)
 
 
 class IntEnumField(EnumField, IntField):