diff --git a/service_container/expression_language.rst b/service_container/expression_language.rst
index 9ba64eee074..0fb5081e15d 100644
--- a/service_container/expression_language.rst
+++ b/service_container/expression_language.rst
@@ -67,7 +67,7 @@ to another service: ``App\Mailer``. One way to do this is with an expression:
             $services->set(MailerConfiguration::class);
 
             $services->set(Mailer::class)
-                ->args([expr("service('App\\Mail\\MailerConfiguration').getMailerMethod()")]);
+                ->args([expr("service('App\\\\Mail\\\\MailerConfiguration').getMailerMethod()")]);
         };
 
 To learn more about the expression language syntax, see :doc:`/components/expression_language/syntax`.