diff --git a/Doc/reference/datamodel.rst b/Doc/reference/datamodel.rst
index 1c2706362b718f..c5a7f046992dd1 100644
--- a/Doc/reference/datamodel.rst
+++ b/Doc/reference/datamodel.rst
@@ -1350,7 +1350,7 @@ Basic customization
 
    .. versionchanged:: 3.7
       ``object.__format__(x, '')`` is now equivalent to ``str(x)`` rather
-      than ``format(str(self), '')``.
+      than ``format(str(x), '')``.
 
 
 .. _richcmpfuncs: