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

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

As Superman comes home to audiences, James Gunn is sharing a glimpse at bringing a new Man of Steel to life. The DC Studios boss shared a behind-the-scenes video from a new featurette for the movie, which is now available on digital,