Who does Sadie Sink play in ‘Spider-Man: Brand New Day’? Her secret character revealed

Warning: Spoilers ahead! Do not proceed unless you’ve watched “Spider-Man: Brand New Day.”

The rumors were true: Sadie Sink is the new Jean Grey.

The “Stranger Things” actress plays the telepathic and telekinetic Marvel superhero in “Spider-Man: Brand New Day,” which was released in theaters Friday.

In “Brand New Day,” Peter (Tom Holland) is plagued by a mysterious new foe who can hop into the brain of any person within 33 feet and completely inhabit their mind.

Midway through the movie, that telepath is revealed to be Jean Grey, a k a Dark Phoenix from “X-Men,” played by Sink.

She’s not evil at all, it turns out, but has been wronged by the Department of Damage Control, which wants to understand and replicate the mind-control powers of her and her sister, Sara

Sink’s Jean Grey is the first “X-Men” character to be properly introduced into the main Marvel Cinematic Universe timeline.

In the 20th Century Fox “X-Men” movies, which are set in a different universe than the MCU films, Famke Janssen played the adult version of Jean, while Sophie Turner played the younger version of the character in the prequels.

Janssen starred in “X-Men” (2000), “X2: X-Men United” (2003) and “X-Men: The Last Stand” (2006). Turner appeared in “X-Men: Apocalypse” (2016) and “X-Men: Dark Phoenix” (2019).

Sink, 24, was widely rumored to be playing the red-headed superhero ever since she was cast in the film in 2025. However, Sink had to stay tight-lipped about her role throughout the press tour.

When she appeared on “The Tonight Show” on Wednesday, host Jimmy Fallon outright asked Sink if plays Jean.

Sink, who kept her composure, replied, “Wouldn’t you like to know.”

Elsewhere in the interview, Sink admitted it’s been “freeing” to not be allowed to talk about her character.

“I get a little nervous for interviews sometimes,” she explained. “And so, if I don’t have to talk about anything, it relaxes me. I’m like, ‘I don’t have anything to say.'”

Six months earlier, Sink told Fallon that she learned of the fan theories about her role even before she was cast in the film.

“There was speculation online that said, ‘Sadie Sink is going to be in the new ‘Spider-Man.’ I was like, ‘Hmm? I am?’” she said on the late-night show in January.

“And sure enough, two days later, they asked me to do it. So yeah, those theories, there’s sometimes some truth to it.”

Days before “Spider-Man 4” came out, MCU boss Kevin Feige told Entertainment Weekly how the team decided Sink was the perfect person to play Jean.

“We had a Peter story that we wanted to tell, and knew that there were a number of characters that could fit into that,” he shared. “And it was Sadie’s name who came up that solidified the idea of the character that she’s playing.”

Holland, for his part, praised Sink’s performance in the film, saying on the press tour that she stole the show.

“She handled the pressure of the character that she’s playing with such grace,” he gushed. “And the third act, she steals the movie. It is so good.”

“Spider-Man: Brand New Day” is in theaters now.