Sideways star Paul Giamatti has joined the cast of corporate thriller Duplicity.

The Universal movie stars Julia Roberts and Clive Owen as ex-lovers who join forces while working as spies for rival firms. Giamatti and Tom Wilkinson will play the heads of competing pharmaceutical companies.

It was previously reported that Billy Bob Thornton was in talks to play one of the businessmen, but no agreement was reached.

Giamatti was nominated for a Best Supporting Actor Oscar in 2005 for his role in boxing epic Cinderella Man.