Yes, that The Fantastic Four: First Steps end credits scene did feature a certain someone in their upcoming role. Warning: Spoilers for The Fantastic Four: First Steps below. Vanessa Kirby confirmed that Robert Downey Jr. was actually the one in the Doctor Doom mask during the film's post-credits moment - even though his face wasn't shown. "Robert's never not been on set. He's always there. He is our leader. We call him our Godfather," Kirby, 37, told Variety in an interview published on Sunday, July 27. "He's looked after us.