Alright Spider-Verse fans you are not gonna believe this. Word just dropped that Sadie Sink yes MAX from Stranger Things is officially joining Tom Holland in the next Spider-Man movie aka Spider-Man 4 ! I know right? Mind. Blown.
From Hawkins to the Hellmouth…Wait, Wrong Franchise! Sadie Sink Enters the MCU in Spider-Man Sequel
The news is out thanks to Deadline and other big outlets and it's seriously exciting. Production is set to kick off later this year and Tom Holland is obviously back as our friendly neighborhood Peter Parker. But the big buzz is around Sadie Sink and who she might be playing. Marvel and Sony are being tight-lipped as usual no official comments yet but the internet is already exploding with theories.
Destin Daniel Cretton who directed Shang-Chi is helming this one so you know it is gonna be good. Amy Pascal and Marvel big boss Kevin Feige are producing too so it's the real deal. Everyone is waiting to see what Cretton brings to the Spider-Man world.
Jean Grey or Redhead Remix? Theories Emerge on Sadie Sink's Mystery Spider-Man Role

Okay so who is Sadie Sink playing? This is the million-dollar question. The biggest theory out there right now is that she will be introduced as Jean Grey. Yes THAT Jean Grey from the X-Men! Think about it: redhead powerful character mutant potential… it kind of adds up right?
IGN and Deadline are both hinting at the Jean Grey possibility especially with Kevin Feige recently teasing that we'd see "X-Men players you might recognize" in upcoming MCU movies. Could this be the start of bringing mutants properly into the MCU? It’s a huge deal if true and Sadie Sink as Jean Grey? Fan-casting perfection.
But hold on there is another theory floating around. Deadline also mentioned she could be playing "another beloved redheaded Spider-Man character." Hmm who could that be? Mary Jane Watson obviously jumps to mind. But with Zendaya already playing MJ Jones in the previous movies things could get a little complicated. Could Sink be a different version of MJ from the multiverse? Or maybe a completely different redhead from Spider-Man comics we haven't even thought of yet? The mystery is part of the fun right?
Significant Role Alert: Expect Sadie Sink to Be More Than Just a Cameo in Spider-Man 4

Whatever role Sink ends up playing reports are saying it will be "significant". This is not just a small appearance or a blink-and-you-miss-it cameo. This sounds like a character who is going to be important to the story and maybe even stick around for future MCU projects. Remember how Spider-Man: No Way Home ended? Peter Parker made everyone forget he is Spider-Man even MJ and Ned. So Spider-Man 4 is likely going to be a bit of a fresh start for Peter in some ways. That means we can expect some changes in his world and new faces taking on bigger roles and Sadie Sink seems to be the first major new addition.
Spider-Man 4 Swings into Production Soon: Tom Holland's Schedule and Release Date Scoop

Tom Holland is a busy guy. He is currently filming Christopher Nolan’s The Odyssey. But don't worry Spider-Man fans the plan is for him to jump right into Spider-Man 4 as soon as he is done with Nolan's project. Filming for Spider-Man 4 is expected to start later this year. As for when we will actually get to see it on the big screen Sony has already set a release date for July 31 2026. Yeah it is a bit of a wait but big superhero movies take time to make and hopefully it will be worth it!
Is This the Start of the MCU's X-Men Era? Sadie Sink Casting Fuels Mutant Mania

Let's zoom out for a second and think about the bigger picture. Marvel has been teasing the arrival of the X-Men into the MCU for a while now. Kevin Feige has hinted that mutants are going to be a big part of the future of the MCU especially after the whole Secret Wars storyline. Could Sadie Sink's casting as Jean Grey be the first step towards a full-blown mutant takeover of the MCU? It definitely feels like things are starting to move in that direction. Imagine a whole new wave of X-Men movies and shows mixing with the Avengers and the rest of the MCU. It is a comic book fan's dream come true!
What's Next for Sadie Sink? From Stranger Things Finale to Broadway and Beyond!

Sadie Sink is having a moment for sure. She just wrapped up filming the final season of Stranger Things which is going to be one of the biggest TV events of 2025. She is also starring in a new musical movie called O’Dessa which just premiered at SXSW and is heading to Hulu soon. And if that's not enough she is making her Broadway debut in a play called John Proctor Is the Villain in April! Talk about booked and busy. Adding Spider-Man 4 to her list just cements her status as one of the hottest young stars in Hollywood right now.
Get Ready for Spider-Man 4 Hype! Sadie Sink Casting Just Took the Anticipation to a Whole New Level

So yeah the news of Sadie Sink joining Spider-Man 4 is HUGE. Whether she is Jean Grey Mary Jane or someone else entirely it is definitely going to shake things up in Peter Parker's world. Get ready for more news theories and maybe even some sneaky set photos as production gets closer. Spider-Man 4 just became one of the most anticipated MCU movies on the horizon and we are here for all of it!