What Is Sadie Sink's Role in 'Spider-Man: Brand New Day'? Her Marvel Character Revealed

Sadie Sink has officially traded Hawkins for the Marvel Cinematic Universe.

In March 2025, Deadline confirmed the Stranger Things actress had joined the cast of Tom Holland's fourth standalone Spider-Man movie, Spider-Man: Brand New Day. Although her character was not revealed at the time, the casting announcement fueled speculation she would portray Jean Grey.

"I found out through online theories. Like, before I got cast in Spider-Man, there was speculation online that said, 'Sadie Sink is going to be in the new Spider-Man.' I was like, 'Hmm? I am?'" she shared in a January interview. "And sure enough, two days later, they asked me to do it. So yeah, those theories, there's sometimes some truth to it."

Following the premiere of the latest MCU film, Sink's mysterious Spider-Man: Brand New Day was finally revealed.

After months of persistent rumors and fan theories, Spider-Man: Brand New Day introduced Sink as Jean Grey. She is the third actress to portray the character in the MCU, following Famke Janssen and Sophie Turner.

During the film's Los Angeles premiere on July 27, musician Steve Lacy accidentally revealed that Jean Grey appears in the movie.

"Out of all of the characters in the film you're aware of and, without spoiling anything, who is your favorite? Or who are you most excited to see?" one reporter asked, to which he responded, "You know, what? Jean. I like Jean. She's the villain, but like, there's a reason to her madness."

"I like her. I like her character. I don't know why," Lacy added.

Sink's Jean Grey, who boasts telepathic and telekinetic abilities, is one of the most powerful X-Men in history. According to Marvel.com, the founding member of the X-Men is the second daughter of John Grey and his wife, Elaine. Her sister, Sara, is portrayed by Olivia Booth-Ford.

In a video posted on Spider-Man Movie's Instagram, Sink gave "three exclusive, confirmed answers" about her character.

"I can confirm I am not Spider-Man," she quipped, adding she is "not Aunt May."

Sink continued, "And third, I can definitely confirm that I am in this movie… As for who I really am, you'll have to find out in the theater."

She also told People at the film's Los Angeles premiere that she had been keeping it as a secret "for a year and a half or however long it's been."