Sadie Sink revealed that Marvel Studios kept the details of her role in Spider-Man: Brand New Day so tightly guarded that she was not given a script until she arrived in London to begin filming.
In a new interview with Nylon, the Stranger Things star shared that she was “offered her role without an audition”, since she had a working relationship with director Destin Daniel Cretton, who cast her in The Glass Castle (2017).
On the secrecy surrounding the production, Sink said: “You just don’t share the secret, it’s not that hard.”
Sink joining the Marvel Cinematic Universe was first reported in March 2025 by Deadline, which only said that she was joining the fourth Spider-Man film alongside Tom Holland as Peter Parker.
Spider-Man: Brand New Day picks up after the events of Spider-Man: No Way Home, with Peter Parker navigating life in a world where nobody remembers his identity. According to the film’s official synopsis, Peter is now operating as Spider-Man full-time in New York while investigating a powerful new threat, as a “surprising physical evolution” in his powers begins to threaten his existence.
Also returning are Zendaya, Jacob Batalon, Jon Bernthal as the Punisher, and Mark Ruffalo as Bruce Banner/Hulk.
However, Marvel is yet to officially disclose Sink’s character, leading to fan theories about who she may be playing, pieced together from set photos.
One of the most persistent theories is that she is cast as Jean Grey, the telekinetic X-Men character previously played by Famke Janssen and Sophie Turner.
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Sink told Nylon the scale of attention surrounding the MCU had still surprised her. “I knew that Marvel was a big deal and had a big brand, especially Spider-Man,” she said. “I know there’s a huge fan base, but it feels really big. I think these blockbuster movies are a whole different beast.”
She credited Holland with helping her settle into the highly secretive production. “It was interesting stepping into that space and being a little bit of an outsider in that way, but he could not have been more welcoming, and just the whole crew in general,” Sink said.
“He was just so relaxed and open, and I felt very at ease.”
Sink is also reportedly set to reprise her role in Avengers: Secret Wars, which is due to begin filming this year.
Late in June, Holland teased that everyone in the film’s universe had forgotten Peter Parker, “except for one person”.
Fans are again theorising that this “person” may be Jean Grey leading to more support for those who believe Sink is playing the character.
Over the past year, Sink has talked about her role and the secrecy around it, but hasn’t given up a single clue for fans.
A set photo showed her covered in a bulky jacket, revealing nothing of her costume, save some locks of her red hair. This alone led fans to conclude she was playing Jean Grey, but Sink only said that “a lot of people forget that hair colour can change”.
Brand New Day is scheduled for release in cinemas on 31 July 2026.
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