Sadie Sink is officially entering the Marvel Cinematic Universe at the end of the month playing a mystery role opposite Tom Holland in “Spider-Man: No Way Home.” Her role is so secretive that Sink has not even appeared in any of the movie’s trailers or marketing footage despite the actor being a Gen Z superstar after her years-long run on Netflix’s “Stranger Things.” Internet sleuths are convinced Sink is playing a young Jean Grey ahead of Marvel introducing a younger band of X-Men into the universe, but she’s not letting anything slip.

“You just don’t share the secret, it’s not that hard,” Sink told Nylon in a new cover story about protecting major franchise secrets.

The publication enticingly adds: “Sometimes even she wasn’t privy to the details [of her Marvel role]: Sink was offered her role without an audition, having worked with director Destin Daniel Cretton on the 2017 film ‘The Glass Castle,’ and she didn’t receive a script until she landed in London.”

“I knew that Marvel was a big deal and had a big brand, especially Spider-Man,” Sink added about all the hoopla around her MCU debut. “I know there’s a huge fan base, but it feels really big. I think these blockbuster movies are a whole different beast.”