Allen & Overy has added the co-chairman of Jenner & Block’s international arbitration practice, U.S. State Department alum Patrick Pearsall, as the firm looks to build up its own practice in the U.S.

Washington, D.C.-based Pearsall, who was also the first-ever chairman of Jenner’s public international law practice, will be a partner in his new firm’s international arbitration and public international law group. Allen & Overy said he’ll lead the expansion of the practice in the Americas.