At San Diego Comic-Con, Avengers: Doomsday star Hayley Atwell gave one of the most detailed accounts yet of filming opposite Robert Downey Jr.'s Doctor Doom, revealing that his in-character presence was so intense it transformed the mood on set. Marvel Studios has kept Downey's take on the villain tightly under wraps, with even his co-stars offering few details, making Atwell's remarks notable for fans eager for clues about the character ahead of the film's release.

Speaking to Collider's Steve Weintraub following Marvel's Hall H panel, Atwell explained she deliberately chose not to ask questions about Doctor Doom because Downey's performance was so convincing it spoke for itself. She described a stark contrast between the actor's easy-going, sociable manner between takes—inviting others to lunch and keeping things fun—and his "enigmatic" and "domineering" presence once in character as Doom. Atwell said she wanted to preserve that unsettling uncertainty during her scenes, retaining a sense that she "didn't know who this person really is" but could feel "a darkness there."