Marvel Studios officially confirmed at San Diego Comic-Con that Hayley Atwell will return as Peggy Carter in "Avengers: Doctor Doom." In an interview with Collider, the actress discussed what Robert Downey Jr. was like on set as the new main villain of the Marvel Cinematic Universe.
According to Atwell, Downey Jr. undergoes a serious transformation when filming begins:
"Between takes, Robert is incredibly open. He calls everyone to lunch together, jokes around, and does everything to make sure the crew has a great time... But when he gets into character as Doom, there's something mysterious and authoritative about him. It's truly frightening."
The actress added that she deliberately did not try to learn more about the character than the script required. She wanted to maintain a sense of the unknown and bring it to the screen:
"I didn't want to destroy that illusion for myself. On screen, I wanted to feel: I don't know who this person really is or what he's capable of, but I know for sure that there's a darkness inside him."
"Avengers: Doctor Doom" is set to premiere on December 18, 2026. In addition to Hayley Atwell and Robert Downey Jr., Chris Evans, Chris Hemsworth, Anthony Mackie, Letitia Wright, Simu Liu, Pedro Pascal, and actors from the Fox-era X-Men films will return to their roles.