The Stranger Things breakout star is set to appear in the upcoming blockbuster Spider-Man: Brand New Day, though Marvel is intentionally shrouding her specific role in a veil of secrecy.
Principal photography for the fourth solo Spider-Man outing starring Tom Holland wrapped up in late December 2025. While Sadie Sink has been confirmed for a pivotal role in the film, there has been no official word on exactly which character she will be bringing to life on the big screen.
During a recent appearance on The Tonight Show Starring Jimmy Fallon to promote the series finale of Stranger Things, the actress confessed that maintaining the studio’s strict level of confidentiality has been an immense challenge.
“It’s absolute torture! There are so many rumors—I feel like every week a new theory pops up about who I’m playing.”
The actress revealed that she keeps a close watch on fan theories, largely because the online community actually predicted her casting before it happened. According to Sink, she first discovered her involvement in the project through social media whispers, just days before receiving an official offer from Marvel Studios.
Since her casting was first announced, fans have been locked in a heated debate over her identity. Sink has been spotted on set alongside Tom Holland, notably keeping her natural red hair. This has fueled speculation that she could be portraying Jean Grey, Mary Jane Watson, or even Mayday Parker—the daughter of Peter Parker from the Tobey Maguire universe. Sink later teased fans further by noting that hair color can easily be changed for a role, only adding to the confusion.
Spider-Man: Brand New Day is scheduled for a theatrical release on July 31. This won’t be Sink’s only appearance in the Marvel Cinematic Universe, however; according to reports from Deadline, the actress is also slated to return for Avengers: Secret Wars, currently eyeing a December 2027 debut.
Source: iXBT.games