Dan Stevens, who played Matthew Crawley in TV's 'Downton Abbey,' has since made four films in America. In 'The Guest,' he's a possibly homicidal American ex-soldier. In 'A Walk Among the Tombstones,' he plays a hardened New York drug trafficker. He also is featured in the upcoming comedies 'The Cobbler' with Adam Sandler, and 'Night at the Museum: Secret of the Tomb' with Ben Stiller.