Linus Roache is joining the cast as assistant district attorney after Jack McCoy (Sam Waterston) vacates the job to serve as New York district attorney, NBC announced.
The English-born Roache starred last season in NBC's short-lived "Kidnapped" and appeared in the films "Batman Begins" and "The Chronicles of Riddick."
"I think he and Sam are going to raise the bar and add intellect and passion" to the "order" half of "Law & Order," series creator and executive producer Dick Wolf said in a statement Tuesday.
McCoy is taking over from New York D.A. Arthur Branch, who was played by Fred Thompson. A former U.S. senator, Thompson asked to be released from the drama as he weighs a bid for the Republican nomination for president.