'Superman': James Gunn Explains How Bradley Cooper Cameo Happened (Exclusive)

'Superman' director James Gunn chats with ET's Cassie DiLaura about his fresh take on the beloved DC hero, in theaters on July 11. The filmmaker shares he never fully sighs a breath of relief when his films come out, despite positive reactions. He reflects on the casting process that led him to finding David Corenswet and Rachel Brosnahan. He also reveals how friend Bradley Cooper landed a cameo in the film.