diff --git a/docs/en/02_Developer_Guides/05_Extending/01_Extensions.md b/docs/en/02_Developer_Guides/05_Extending/01_Extensions.md
index fedd77a8b..6fd32962b 100644
--- a/docs/en/02_Developer_Guides/05_Extending/01_Extensions.md
+++ b/docs/en/02_Developer_Guides/05_Extending/01_Extensions.md
@@ -90,7 +90,7 @@ class MyMemberExtension extends DataExtension
     ];
 
     private static $has_one = [
-        'Image' => 'Image',
+        'Image' => Image::class,
     ];
 
     public function SayHi()