diff --git a/php/src/Google/Protobuf/Internal/Message.php b/php/src/Google/Protobuf/Internal/Message.php
index 1d1fbf27c560..7af69304decd 100644
--- a/php/src/Google/Protobuf/Internal/Message.php
+++ b/php/src/Google/Protobuf/Internal/Message.php
@@ -54,6 +54,7 @@
  * or extend this class or its child classes by their own.  See the comment of
  * specific functions for more details.
  */
+#[\AllowDynamicProperties]
 class Message
 {