Sidley Austin is adding a partner in Hong Kong.

Thomas Deegan will join from British firm Simmons & Simmons, where he had been a Hong Kong-based partner since 2007. He is expected to start at Sidley within the next month.

Deegan focuses primarily on energy and natural resources transactions. Last year, he and fellow Hong Kong partner Vivien Yang led the Simmons & Simmons team that advised India’s Oil & Natural Gas Corp. on its $1 billion purchase of oil field stakes in the Caspian Sea from New York-based Hess Corp.

Deegan was a partner at the former Wilde Sapte in Tokyo in 1999. He stayed with the firm when it merged with Denton Hall a year later, working in its Dubai and Hong Kong offices until he moved to Simmons & Simmons.

About seventy lawyers work in Sidley Austin’s Hong Kong office, including 16 partners. The firm employs about 1,700 lawyers in 18 offices worldwide.