You won't find a cinematic event in 2026 that will be bigger than Avengers: Doomsday. Spider-Man: Brand New Day might match it in box office takings, but that's a whole other story. Either way, the Marvel Cinematic Universe is set to enjoy a hugely successful year. The Multiverse Saga is set to come to an end with those two films, plus another Avengers in 2027, and there is a reason that the world is talking about Avengers: Doomsday.
Robert Downey Jr. returns to the MCU in the new role of antagonist Doctor Doom, as he is set to step forward as the Multiverse Saga's new Big Bad. How he takes the spotlight from former villain Kang the Conqueror remains to be seen, but one thing is certain: A huge range of heroes are going to be needed to stop him. And that's why Marvel made audiences watch a five-hour livestream as they slowly announced the cast for the upcoming movie.
There were some noticeable absences, though, including some cast members who had already been announced as returning parts of the movie. Now, they have been re-confirmed.
Agent Carter will return to the MCU in Avengers 5 and 6
Hayley Atwell will return to the Marvel Cinematic Universe as Peggy Carter in both Avengers: Doomsday and Avengers: Secret Wars. The Hollywood Reporter confirmed as much in a recent round-up of Hollywood's most powerful lawyers in 2025, revealing that Julian Zaifen oversaw "Hayley Atwell's deal to star in Marvel's Avengers 5 and 6".
No other information about the deal was provided, but this little detail is bigger than you might initially realize. See, Atwell was previously confirmed to appear in Avengers: Doomsday back in December by Deadline. That report was never officially confirmed by Marvel Studios, who recently unveiled the cast list for the upcoming movie. Atwell's name was absent from that announcement, which led fans to believe that Marvel's plans for the movie - which had undertaken a number of major changes over the past few years - had changed again.
Although Marvel has confirmed that more surprises await, there was still uncertainty about whether Atwell would be among the returnees. This report now confirms that she will be, which leads to the inevitable speculation about which version of Peggy Carter she might be playing (Multiverse Saga problems, amirite?).
Atwell is an MCU veteran, having first appeared as Peggy in 2011's Captain America: The First Avenger before reprising the role in the 2014 TV series Agent Carter. She also appeared in smaller roles as the character in Captain America: The Winter Soldier, Avengers: Age of Ultron, and Avengers: Endgame. In the MCU continuity, Carter died in her old age in The Winter Soldier, but lived on in an alternate timeline in Endgame which saw the character's arc wrapped up when Steve Rogers went back in time to live a happy life with her.
Ever since the Multiverse Saga, Atwell has played an alternate version of the character. Captain Carter, a variant who came about after taking the Super Soldier Serum instead of Steve Rogers, went on to become the face of animated series What If...? She also played an alternate version of Captain Carter in live-action film Doctor Strange in the Multiverse of Madness.
With all of that in mind, the question is: Which version of Peggy Carter will show up in Avengers: Doomsday and Avengers: Secret Wars? Technically, all three of them died in the MCU's main continuity, with What If...?'s version of Captain Carter sacrificing herself in a battle against The Watchers. But fans aren't convinced that she's truly gone. Could that version make her live-action debut in the two Avengers movies?
Of course, the most likely variant of the character to appear is the original Agent Peggy Carter. With rumors that Chris Evans will return as the original Captain America, it makes sense that we catch up with the pair who are currently living happily ever after in an alternate version of the 1940s or 1950s. And given that they are to of the MCU's original heroes, it's only fitting that they be present for the end of the Multiverse Saga.
Avengers: Doomsday is released on May 2, 2026. Avengers: Secret Wars arrives on May 7, 2027.