diff --git a/docs/api-guide/fields.md b/docs/api-guide/fields.md
index 0492af9aa..04f993942 100644
--- a/docs/api-guide/fields.md
+++ b/docs/api-guide/fields.md
@@ -583,6 +583,7 @@ The serializer method referred to by the `method_name` argument should accept a
 
         class Meta:
             model = User
+            fields = '__all__'
 
         def get_days_since_joined(self, obj):
             return (now() - obj.date_joined).days