Sadie Sink’s role in Spider-Man 4 sparks new Jean Grey theories

Another speculation has surfaced regarding the mystery character played by Stranger Things star Sadie Sink in Marvel Studios’ eagerly awaited Spider-Man: Brand New Day. Starring Tom Holland, the film is scheduled to hit theatres on July 31, 2026.

According to a recent rumor from “The Beyond Reporter” on X, Sink’s true identity within the Marvel Cinematic Universe will not be revealed immediately. Audiences will allegedly be led to believe she is portraying a minor, original figure before it is revealed that her character’s name is actually Jean. This rumored twist draws comparisons to the “MJ” surprise at the end of 2017’s Spider-Man: Homecoming, where it was revealed that Zendaya’s character was “Michelle Jones” rather than the traditional Mary Jane.

Sadie Sink in Spider-Man: Brand New Day will lead audiences to believe she’s a random character, but in the film’s third act, it will be revealed that her name is Jean. pic.twitter.com/6laJABBhe7

— The Beyond Reporter (@BeyondReporter_) January 17, 2026

Prior to this latest rumor, many fans speculated that Sink might be the MCU’s Jean Grey, especially following reports that she will also appear in Avengers: Secret Wars. Conversely, other reports have suggested she could be playing Rachel Summers, the daughter of Jean Grey and Scott Summers in the comics.

Spider-Man: Brand New Day is directed by Destin Daniel Cretton, with a screenplay by Chris McKenna and Erik Sommers. Jacob Batalon returns as Ned Leeds, and Emmy-winner Zendaya reprises her role as MJ. Joining them are Sadie Sink, Jon Bernthal (returning as Frank Castle/The Punisher from Daredevil: Born Again), Liza Colón-Zayas, and Tramell Tillman. According to earlier rumors, Tillman may portray the new head of the Department of Damage Control.