According to empireonline.com, Irvine will star as young Albert, whose horse, Joey, is sold to the British army and serves on the French battlefields in World War I. Watson and Mullan will play Albert's parents, and Cumberbatch has been cast as Major Stewart. The cast is also set to include Niels Arestrup, Celine Buckens, Nicolas Bro, David Kross, Leonard Carow, Rainer Bock, Robert Emms (who recently played Albert in the West End production) and Patrick Kennedy. Tom Hiddleston and Stephen Graham are also reportedly in negotiations to appear.

Lee Hall (a Tony winner for his book to Billy Elliot) and Richard Curtis will co-adapt the film's screenplay.

The imaginative National Theatre production of War Horse, based on Morpurgo's novel, has made its way to London's West End and will be seen at Lincoln Center's Vivian Beaumont Theater in March 2011. The play is adapted by Nick Stafford and directed by Marianne Elliott and Tom Morris.