Hollywood stars Robert Downey Jr. and Matt Damon have joined the cast of Christopher Nolan's upcoming World War II epic 'Oppenheimer', a film about the development of the atomic bomb.

Murphy is portraying the theoretical physicist who helped develop the atomic bomb during World War II. According to sources, Blunt is playing his wife, Katherine "Kitty" Oppenheimer, while Damon will play Lt. Gen. Leslie Groves, the director of the Manhattan Project, the US research initiative that developed the first atomic bomb.