Boies, Schiller & Flexner said Thursday that it has hired David Pressman, a senior U.S. envoy to the United Nations who has close ties to actor George Clooney and his wife, international human rights lawyer Amal Clooney.

Pressman, 39, is expected to join Boies Schiller’s New York office as a partner on Monday. He is leaving his government post after more than two years as U.S. Ambassador to the U.N. for Special Political Affairs, where he was close deputy to U.S. Ambassador to the U.N. Samantha Power and played a key role in U.N. Security Council negotiations.