diff --git a/rest_auth/serializers.py b/rest_auth/serializers.py
index 6157f37..a2c11ad 100644
--- a/rest_auth/serializers.py
+++ b/rest_auth/serializers.py
@@ -126,7 +126,7 @@ class UserDetailsSerializer(serializers.ModelSerializer):
     """
     class Meta:
         model = UserModel
-        fields = ('id', 'username', 'email', 'first_name', 'last_name')
+        fields = ('pk', 'username', 'email', 'first_name', 'last_name')
         read_only_fields = ('email', )