Russo brothers describe Robert Downey Jr.'s Doctor Doom voice as a defining moment

Directors Joe and Anthony Russo said Robert Downey Jr. surprised them by delivering an improvised Doctor Doom voice during a discussion of the character’s details, noting that the vocal choice would be crucial for the masked villain. Anthony Russo told a media outlet that the moment “was something that Robert surprised us with one day,” and the brothers felt it was the definitive direction for the role.

"We were talking about all the details of the character: the voice, of course, is a key part of it, especially in the mask. So one day … he broke out into the voice. And we knew at that moment, that was it," Russo said. Joe Russo added that hearing the voice gave him a strong reaction, likening it to the emotional impact of Tony Stark’s sacrifice in Avengers: Endgame. "Robert tends to present a lot of those super memorable moments," he said. The casting of Downey Jr. as Doctor Doom has sparked mixed responses among Marvel fans, with some critics comparing the accent to a poor Dracula impression. Marvel Studios president Kevin Feige responded to concerns about the character’s sudden introduction by drawing a parallel to Thanos’ buildup before Infinity War. A new line of toys released ahead of the film hints at Shang-Chi’s involvement as a potential opponent for Doom. Avengers: Doomsday is scheduled to open in cinemas on December 18.