diff --git a/lib/ansible/modules/cloud/vmware/vca_nat.py b/lib/ansible/modules/cloud/vmware/vca_nat.py
index e2d5bb192d..c0407a846b 100644
--- a/lib/ansible/modules/cloud/vmware/vca_nat.py
+++ b/lib/ansible/modules/cloud/vmware/vca_nat.py
@@ -126,7 +126,7 @@ def rule_to_string(rule):
     strings = list()
     for key, value in rule.items():
         strings.append('%s=%s' % (key, value))
-    return ', '.join(string)
+    return ', '.join(strings)
 
 def main():
     argument_spec = vca_argument_spec()