Despite Marvel fans still being in the dark over which comic book hero Sadie Sink is playing in Spider-Man 4, it seems as though the character is important enough to appear in further MCU movies, including Avengers: Secret Wars.
As reported by Deadline, Sink has joined the cast of Avengers: Secret Wars and is due to start shooting in London later in 2026. Marvel Studios has yet to confirm the news.
Marvel is keeping its cards close to its chest in terms of the sixth Avengers movie, with no official synopsis or cast list available just yet. We do know that Robert Downey Jr. will appear as Doctor Doom, as well as the new Fantastic Four, Pedro Pascal as Mister Fantastic, Vanessa Kirby as Sue Storm, Joseph Quinn as Johny Storm, and Ebon Moss-Bachrach as the Thing.
As for Sink, the Stranger Things star is set to make her Marvel debut in Spider-Man: Brand New Day in an undisclosed role. Both Marvel and Sink are remaining very tight-lipped over her character, with Sink shutting down questions regarding the elusive role. But this hasn't stopped fans from guessing who she could be playing, from X-Men's Jean Grey to one of Peter Parker's love interests, Gwen Stacy.
The Secret Wars news has fans theorising even further. "She’s definitely playing Firestar, who is an X-Man and Avenger in the comics," said one fan on Twitter, and another replied, "So she's either Mayday Parker, Firestar, or Jean Grey." Whoever she is, the character must be crucial enough to break out of the Spider-Man world.
Spider-Man 4 is directed by Shang-Chi and the Legend of the Ten Rings' Destin Daniel Cretton, and also stars Jon Bernthal as the Punisher and Michael Mando as Scorpion. Spider-Man: Brand New Day arrives in theaters on July 31, 2026.
Avengers: Secret Wars will be released on December 17, 2027. For more, check out our list of the most exciting upcoming movies and upcoming Marvel movies and shows on the way in 2025 and beyond.
