Sadie Sink Joins MCU as Jean Grey in Spider-Man: Brand New Day

Sadie Sink has officially entered the Marvel Cinematic Universe, taking on the role of Jean Grey in Spider-Man: Brand New Day, now in cinemas. The reveal answers months of speculation about the red-haired Stranger Things breakout's involvement in the film.

In the movie, Sink plays a mutant with psychic powers who becomes the film's central antagonist. Her character operates in the shadows for much of the narrative—her face remains unrevealed until roughly halfway through the film. She uses her abilities to possess and control nearby people's minds, attempting to infiltrate the Department of Damage Control to retrieve something locked in its vault. According to Variety, her character targets the Hulk (Mark Ruffalo) as a more powerful vessel to breach the organization's defences.

The film positions Damage Control itself as the true villain. While imprisoned by the agency's CEO Bill Metzger (Tramell Tillman), Sink's Jean discovers she shares a tragic past with the organisation: a flashback reveals her older sister Sara also possessed psychic abilities and was abducted and killed by Damage Control scientists. This trauma drives Jean's vendetta, culminating in a psychic event that paralyses much of New York City.

A Bridge to the X-Men Era

Spider-Man (Tom Holland) is the only person able to overcome Jean's powers. In a pivotal scene, he connects with her through shared memories—including a tender recollection of his late Aunt May (Marisa Tomei)—and persuades her to stand down. The encounter is interrupted when the Punisher (Jon Bernthal) attempts a sniper shot at the mutant; Spider-Man takes the bullet protecting Jean, who uses her abilities to keep him alive before departing the city.

The film's final moments suggest Jean may be heading to the Xavier School for Gifted Youngsters, hinted at by her boarding a bus out of the city as autumn foliage appears on screen. Though Brand New Day contains no explicit references to the X-Men or other mutants, the trajectory is unmistakable.

What's Next for the MCU

Sink becomes the third actor to portray Jean Grey in live-action film. Famke Janssen embodied the character in Fox's original X-Men trilogy, while Sophie Turner took on a younger version in the prequel series. The MCU has already begun integrating legacy X-Men cast members—Hugh Jackman, Ryan Reynolds, Patrick Stewart and Kelsey Grammer have reprised their Fox roles, with Stewart and Grammer set to appear in Doomsday alongside James Marsden, Ian McKellen, Rebecca Romijn, Alan Cumming and Channing Tatum.

With Sink's casting, the studio appears to be building a younger generation of mutants for the MCU's expanding roster. Marvel has not yet announced details about the planned X-Men film's cast or release date, though Sink's introduction suggests she will feature prominently in that chapter.