Benedict Cumberbatch, Colin Firth, Richard Madden and Mark Strong are joining the cast of Sam Mendes’ drama “1917,” which will begin production on April 1.

Andrew Scott, Daniel Mays, Adrian Scarborough, Jamie Parker, Nabhaan Rizwan and Claire Duburcq also join a cast that already includes George MacKay and Dean-Charles Chapman. Mendes is both writing (alongside Krysty Wilson-Cairns) and directing “1917.”

The film follows two young British soldiers on a single day at the height of World War I.

Also Read: Sam Mendes' WWI Epic '1917' Set for Holiday 2019 Release

Mendes also produces the film with Pippa Harris (his partner at Neal Street Productions) and Jayne-Ann Tenggren and Callum McDougall. Michael Lerman is co-producing. The project will shoot in England and Scotland.

Neal Street Productions is producing for DreamWorks Pictures and Universal Pictures. The film is set for release on December 25. Mendes made his first feature, “American Beauty,” under the DreamWorks label.