Cillian Murphy said it "took a toll" to play J Robert Oppenheimer in Christopher Nolan's new film about the physicist who co-created the first atomic bomb. The Irish actor, 47, added that the "moral dilemmas and paradoxes" his character grapples with throughout the film are "huge". "It does take a toll, but in a brilliant way, it was the biggest, most exhilarating challenge," Murphy said, ahead of Oppenheimer's release.The film recounts the famous physicists' fears that tests for the first atomic bomb could have destroyed the planet. Oppenheimer releases on Friday 21 July.