Steven Spielberg will direct the film, according to Variety. The motion picture, which will begin shooting in late summer or early fall, will be released Aug. 10, 2011, by Disney and DreamWorks.
Producers include Spielberg as well as Kathleen Kennedy, Frank Marshall and Revel Guest.
The novel about a boy and his horse over the course of World War I was a runner-up for the Whitbread Award in the U.K. The stage version was a huge hit for the National.
"From the moment I read Michael Morpurgo's novel 'War Horse,' I knew this was a film I wanted DreamWorks to make," Spielberg said. "Its heart and its message provide a story that can be felt in every country."
Spielberg recently dropped plans to remake "Harvey," based on the play of the same name.
Variety also reports that DreamWorks has optioned the rights to the stage play.
Lincoln Center Theater will then team with the National Theatre of Great Britain, in association with Bob Boyett, to present the U.S. premiere of the National Theatre's critically acclaimed production of War Horse, based on the novel by Michael Morpurgo and adapted by Nick Stafford, with direction by Marianne Elliott and Tom Morris. It will begin performances at the Vivian Beaumont March 17, 2011, with an opening night scheduled for April 14, 2011.