Steven Spielberg's latest project, 'The War Horse' appears to be on the fast track with the unveiling of his main cast, most of them familiar British actors.Emily Watson, Peter Mullan, David Thewlis and Benedict Cumberbatch have all signed on the dotted line, but taking the lead (or the reins) is young actor Jeremy Irvine, who has earned his stripes with both the National Youth Theatre and the RSC.Adapted from Michael Morpurgo's acclaimed 1982 children's novel, "War Horse" follows a young man named Albert whose beloved horse, Joey, is sold to the cavalry and sent off for active duty in World War I.