No definitive proof, but this points to the belief it is possibly him:
Clement: Otherwise unmentioned in the NT. Early Christian tradition identifies him as Clement of Rome, the fourth bishop of Rome (after Peter, Linus, and Anacletus) and the author of an ancient epistle known as 1 Clement (Eusebius, Ecclesiastical History 3, 15–16; St. Jerome, On Illustrious Men 15).
Ignatius Press. (2010). The Ignatius Catholic Study Bible: The New Testament (Revised Standard Version; Second Catholic Edition., p. 361). San Francisco: Ignatius Press.