Sadie Sink is remaining tight-lipped about her mysterious role in Spider-Man: Brand New Day

Speculation surrounding who the Stranger Things star will portray in the upcoming superhero film began in March 2025, when she was cast. Since then, the internet has been riddled with fan theories about her mysterious character. According to Spider-Man: Brand New Day director Destin Daniel Cretton, there’s actually a “very real reason” why Sink’s character is shrouded in mystery. 

“If people are gonna get mad, I can’t control that! I wish everything was a secret,” Cretton recently told Rolling Stone. “Some people wanna know everything, and some people don’t. There are certain people like me — if I know I’m gonna watch a movie, I try not to even watch the trailers.”

Cretton believes that when fans watch the film, they’ll understand why Sink’s role was kept under wraps. 

“You’ll see when you watch the movie that there’s a very real reason not to tell people who Sadie Sink is playing,” he said. “And I don’t think you’ll get mad at it. I think you’ll be like, ‘Oh, I’m glad I didn’t know that.'”

Sadie Sink in Spider-Man: Brand New Day.

Sink in Spider-Man: Brand New Day.

(Christopher Polk/Deadline via Getty Images)

In a July 17 promo video shared on the Spider-Man: Brand New Day social media accounts, Sink jokingly leaned into the speculation.  

“Since the trailer dropped, I’ve seen so many theories about who I’m playing,” Sink said. “To match your incredible energy, I’ve decided to give you three exclusive, confirmed answers right now.”

Sink playfully continued, “I can confirm I am not Spider-Man. Second, I can confirm I am not Aunt May. And third, I can definitely confirm that I am in this movie.” 

Among the leading fan theories is that Sink will portray Jean Grey, a core member of the X-Men. During the Los Angeles premiere for the movie on Monday, July 27, musician Steven Lacy, whose track “Oh Yeah?” is featured in the film, raised some eyebrows when he was asked which character he’s most excited to see in it.

“Jean,” Lacy said. “I like Jean. She’s the villain but there’s a reason to her madness.”

When asked if he had just shared a spoiler, Lacy replied, “I like her. I like her character. I don’t know why.”

Although Lacy didn’t connect Jean Grey to Sink’s character, it wasn’t long before the internet erupted in a frenzy: Had he just confirmed what everyone suspected?

Although Sink has remained mum about the details of her character, she did praise Spider-Man himself, Tom Holland, for making her feel welcome on set as a newcomer. Spider-Man: Brand New Day marks Sink’s first foray into a major, multi-film superhero franchise. 

“It was interesting stepping into that space and being a little bit of an outsider in that way, but [Holland] could not have been more welcoming, and just the whole crew in general,” she told Nylon for its summer cover story. “He was just so relaxed and open, and I felt very at ease.”

HOLLYWOOD, CALIFORNIA - JULY 27: (L-R) Sadie Sink, Jon Bernthal, Tom Holland, Zendaya and Jacob Batalon attend the Los Angeles Premiere of Columbia Pictures' "Spider-Man: Brand New Day" at Dolby Theatre on July 27, 2026 in Hollywood, California. (Photo by Axelle/Bauer-Griffin/FilmMagic)

Sadie Sink, Jon Bernthal, Tom Holland, Zendaya and Jacob Batalon attend the Los Angeles premiere of Spider-Man: Brand New Day on July 27.

(Axelle/Bauer-Griffin via Getty Images)

Holland, who has a history of accidentally leaking plot points from Marvel movies, has also kept quiet. He did, however, praise Sink’s performance in the film.

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

Sink, who attended her first photocall with the Spider-Man: Brand New Day cast on July 17, was offered the undisclosed role without an audition.  

“I think I just really wanted to play the character. To join the world of the Spider-Man universe is amazing — I’m such a fan,” she told Access Hollywood. “[Cretton] talked me through the character and what he had in mind, and [he’s] obviously someone that I’d worked with before, so I was very comfortable with. So that kind of made it a no-brainer for me.”