diff --git a/peps/pep-0621.rst b/peps/pep-0621.rst
index d5c416c8f..2ad264757 100644
--- a/peps/pep-0621.rst
+++ b/peps/pep-0621.rst
@@ -20,6 +20,9 @@ Post-History: 22-Jun-2020,
 Resolution: https://discuss.python.org/t/pep-621-round-3/5472/109
 
 
+.. canonical-pypa-spec:: :ref:`packaging:pyproject-toml-spec`
+
+
 Abstract
 ========