Tom Holland's Spider-Man 4 Casts A Stranger Things Star – Let's Guess Which Marvel Character She's Playing

Deadline reports that Sadie Sink has joined the cast of Tom Holland's upcoming fourth Spider-Man film. Sink is a rising star, having broke out with her role as Max Mayfield on "Stranger Things." She's since gone on to make notable appearances in the "Fear Street" films and play a supporting part in Darren Aronofsky's Brendan Fraser comeback vehicle, "The Whale."

The report does not say which character Sink is playing, and it may be more complicated than it appears. Now, Sink's red hair should set off all of your spider-senses. The obvious conclusion is that she'll be playing Mary Jane Watson, Peter Parker's famously red-haired girlfriend. But doesn't Tom Holland's Peter already have an MJ?

In the Jon Watts-directed "Spider-Man" trilogy, Holland's Peter Parker got together with Michelle "MJ" Jones (Zendaya). Now, "Spider-Man: No Way Home" ended with MJ losing her memories of Peter, and he decided to leave well enough alone. Zendaya's MJ did not look or act much like the classic MJ; she was a cynical loner, not the life of the party or a girl next door. Plus, since her name literally wasn't "Mary Jane," there's some wiggle room to possibly introduce the real Mary Jane Watson, played by Sadie Sink.

Except, Sink has reportedly already been in the running for a different Marvel redhead: Jean Grey of the X-Men.

Jeff Sneider reported in December 2024 that Sink was the frontrunner to play Jean in Marvel Studios' "X-Men" reboot. Deadline also notes in its casting announcement that "the prevailing theory is [Sadie Sink] will be introduced as X-Men character Jean Grey." At the same time, the article admits Sink could, in fact, be playing Mary Jane instead.

Holland's previous "Spider-Man" films also prominently featured guest stars: Robert Downey Jr. as Tony Stark, Samuel L. Jackson as Nick Fury in "Far From Home," and then Tobey Maguire and Andrew Garfield's Peter Parkers, plus all of their major villains, in "No Way Home." (Not to mention Benedict Cumberbatch as Doctor Strange.)

Perhaps Marvel intends to use "Spider-Man 4," a guaranteed hit, to springboard its "X-Men" reboot for the Marvel Cinematic Universe. Like Spider-Man, the X-Men are typically teenage outcast heroes, so there's commonality to explore. Peter and Jean, however, don't have much of a comics history to build off of. This exchange from Brian Michael Bendis and Mark Bagley's "Ultimate Spider-Man" is the most memorable conversation they've had:

Marvel Comics

Then again, in "Ultimate Spider-Man," Peter dated the X-Men's Kitty Pryde for a bit — perhaps the new "Spider-Man" movie will do that storyline, but with Jean (the no. 1 X-Woman) rather than Kitty? Jean would also definitely be a temporary love interest for Peter, which would leave the door open to bring back Zendaya's MJ. 

Admittedly, bringing back MJ and Ned Leeds (Jacob Batalon) would undermine the ending of "No Way Home" and its themes of responsibility; Batalon, in particular, has said he wouldn't mind sitting future "Spider-Man" movies out. But since Holland and Zendaya are a real-life power couple now, the temptation to bring MJ back must be strong.

"Spider-Man 4," directed by Destin Daniel Cretton, is tentatively scheduled to open in theaters on July 31, 2026.