diff --git a/src/Symfony/Component/VarDumper/Caster/Caster.php b/src/Symfony/Component/VarDumper/Caster/Caster.php
index b6a84fcbe6984..32c69ee04dc43 100644
--- a/src/Symfony/Component/VarDumper/Caster/Caster.php
+++ b/src/Symfony/Component/VarDumper/Caster/Caster.php
@@ -36,6 +36,8 @@ class Caster
     public const PREFIX_VIRTUAL = "\0~\0";
     public const PREFIX_DYNAMIC = "\0+\0";
     public const PREFIX_PROTECTED = "\0*\0";
+    // usage: sprintf(Caster::PATTERN_PRIVATE, $class, $property)
+    public const PATTERN_PRIVATE = "\0%s\0%s";
 
     /**
      * Casts objects to arrays and adds the dynamic property prefix.