diff --git a/lib/ansible/plugins/lookup/cartesian.py b/lib/ansible/plugins/lookup/cartesian.py
index ce31ef9700b..75d3a0735a8 100644
--- a/lib/ansible/plugins/lookup/cartesian.py
+++ b/lib/ansible/plugins/lookup/cartesian.py
@@ -50,5 +50,5 @@ class LookupModule(LookupBase):
         if len(my_list) == 0:
             raise AnsibleError("with_cartesian requires at least one element in each list")
 
-        return [self._flatten(x) for x in product(*my_list, fillvalue=None)]
+        return [self._flatten(x) for x in product(*my_list)]