diff --git a/src/Models/Types/Resources/IRI.php b/src/Models/Types/Resources/IRI.php
index 0a5fe5dd95325587dd6fa6f27d2b6eb6cc3a95ee..1c2b3b3691814678916218c1492e15c78c84f63a 100644
--- a/src/Models/Types/Resources/IRI.php
+++ b/src/Models/Types/Resources/IRI.php
@@ -68,7 +68,7 @@ final class IRI extends AbstractType
      */
     public function castToStringOrStringArray(string $expr): string
     {
-        return $expr;
+        return sprintf('%s.toString()', $expr);
     }
 
     /**