diff --git a/reference/spl/splobjectstorage/offsetexists.xml b/reference/spl/splobjectstorage/offsetexists.xml
index 6ec5b7a487..4a7367d17e 100644
--- a/reference/spl/splobjectstorage/offsetexists.xml
+++ b/reference/spl/splobjectstorage/offsetexists.xml
@@ -16,6 +16,11 @@
   <para>
    Checks whether an <type>object</type> exists in the storage.
   </para>
+  <note>
+   <para>
+    <methodname>SplObjectStorage::offsetExists</methodname> is an alias of <methodname>SplObjectStorage::contains</methodname>.
+   </para>
+  </note>
  </refsect1>
 
  <refsect1 role="parameters">