diff --git a/reference/datetime/dateinterval/format.xml b/reference/datetime/dateinterval/format.xml
index b606ae09af..3093c79d04 100644
--- a/reference/datetime/dateinterval/format.xml
+++ b/reference/datetime/dateinterval/format.xml
@@ -231,6 +231,15 @@ echo $interval->format('%m month, %d days');
   </para>
  </refsect1>
 
+ <refsect1 role="seealso">
+  &reftitle.seealso;
+  <para>
+   <simplelist>
+    <member><methodname>DateTime::diff</methodname></member>
+   </simplelist>
+  </para>
+ </refsect1>
+
 </refentry>
 
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