"For you to talk about how it's OK to be vulnerable, you have to be vulnerable," Gunn told the "Superman" star

Superman director James Gunn has shared a clip from Adventures in Making Superman, a 60-minute documentary showcasing the intimate behind-the-scenes story of Gunn’s first DC Universe movie. The documentary is part of the movie’s digital release,

"I love David," says Gunn. "One of my favorite actors I've ever worked with. He is wonderful. He also questions everything."