Dan Stevens, of “Downton Abbey”, is playing Lancelot in Fox’s “Night at the Museum 3″, according to Deadline.
The new movie, set in London, will see Ben Stiller reprising his role as museum security guard Larry Daley, with Robin Williams playing Theodore Roosevelt.
Shawn Levy, who directed the first two installments, will direct the third.
Production is due to begin early next year on the movie.
Stevens’ Lancelot role is said to be a pivotal part of the movie.