Oscar Isaac Pulls Out of Star Wars Celebration, and Now MCU Fans Think Moon Knight Is in Avengers: Doomsday

OK, roll with us on this one... Oscar Isaac might just be returning as Moon Knight, and in Avengers: Doomsday no less. Shocked? Us too, but there’s one particular recent development that is starting to make the theory seem plausible.

Earlier in the weekend, Star Wars Celebration’s official social media revealed that Isaac would no longer be making an appearance at the beloved convention in Japan this year “due to changes in his production schedule.”

Isaac's appearance at Star Wars Celebration was a headline-grabbing announcement back in February, sparking rumors of Poe Dameron's return to the galaxy far, far away. Rey actress Daisy Ridley appeared at Star Wars Celebration 2023 to announce she would appear in a new film, so fans were wondering if Isaac would do something similar here.

Naturally, Isaac's production schedule changes were not detailed, but considering Avengers: Doomsday is currently in production in London, it didn't take long for fans to put two and two together to come up with Moon Knight in Avengers.

He’s gonna be filming doomsday?— James Young (@YoungJames34) April 4, 2025

Dooooomsday— G the Gamer (@G_da_Gamer) April 4, 2025

Doomsday— Taco John (@SWaddict_) April 4, 2025

That said, the theory is still just a theory. Marvel does like surprises, but the fact remains that Isaac wasn’t actually one of the many announced names in the Doomsday cast reveal. However, Marvel Studios producer Kevin Feige did confirm that the livestream did not include the entire cast of Doomsday — “We revealed many, not all,” he said over a video call at CinemaCon — so we can dream, can’t we?

One six-episode season of Moon Knight was released back in 2022 starring Isaac, but Marvel has yet to announce a follow-up. Avengers: Doomsday is set to hit theaters on May 1, 2026, with a whole host of returning heroes and famous faces bringing the story to life as per the epic livestream.

Meanwhile, MCU fans have also turned their inquisitive gaze upon Robert Downey Jr’s hair after the Iron Man actor recently sent out a Doctor Doom-themed invitation for this 60th birthday party.

Last month's Avengers: Doomsday cast reveal was heavy on veteran X-Men actors. Kelsey Grammer, Patrick Stewart, Ian McKellen, Alan Cumming, Rebecca Romijn, and James Marsden are all now set to appear in Avengers: Doomsday, confirming the X-Men are in the film in a big way. Grammer famously played Beast in the Fox X-Men franchise before making his MCU debut via The Marvels' post-credits scene. Stewart played Charles Xavier/Professor X in the X-Men films before appearing briefly in the MCU via Doctor Strange in the Multiverse of Madness as a member of the Illuminati. McKellen, who played Magneto, has yet to appear in the MCU. Neither has Cumming, who played Nightcrawler, Romijn, who played Mystique, nor Marsden, who played Cyclops. It begs the question: is Avengers: Doomsday secretly an Avengers vs. X-Men movie?

Lex Briscuso is a film and television critic and a freelance entertainment writer for IGN. You can follow her on Twitter at @nikonamerica.