Sadie Sink plays Mary Jane Watson in a newSpider-Man 4theory that links her to Zendaya’s Michelle Jones, giving theMarvel Cinematic Universetwo MJs. The next ofTom Holland’s Spider-Man movieshas not yet had many details revealed. The film will enter production later this year when Holland and Zendaya wrap up director Christopher Nolan’sThe Odyssey.Spider-Man 4’s storyis a secret as of this moment, but even though Marvel and Sony have mostly kept quiet about the film’s development,the first major casting update for the MCU movie came recently.

Sadie Sink has joinedSpider-Man 4. The actress became known worldwide for her role as Max Mayfield inStranger Things, one of the most popular characters on Netflix’s flagship show. Her casting is exciting, and the fact that Sink’s character has not been disclosed yet has led to many theories about who she could play. The casting report pointed at X-Men’s Jean Grey, who Sink had previously been rumored to play in the MCU, as her Marvel character. However, it alsoteased that she could be playing Mary Jane Watson, and a newSpider-Man 4theory makes her MJ’s sister.

Tom Holland’s unmasked from No Way Home, Robert Downey Jr.’s Doctor Doom from the 2024 SDCC announcement and Hugh Jackman’s Wolverine from Deadpool & Wolverine

Zendaya’s MJ Will Reportedly Have A Minor Role In Spider-Man 4

Spider-Man: No Way Home Set That Up

While Marvel and Sony have yet to comment on the directionSpider-Man 4is headed in, multiple reports about possible characters and storylines have emerged over the past year. Among them is the possible nature of MJ’s role.Zendaya has already been confirmed to return for the film, with Holland saying that he read the MCU movie’s script with her, and the two bounced around the room with excitement. However,Zendaya’s MJ will reportedly have a reduced role inSpider-Man 4, which makes sense due to in-universe reasons and the actress' upcoming projects.

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Spider-Man: No Way Home’s ending paved the way for Zendaya’s MJ and Jacob Batalon’s Ned Leeds to play smaller roles if they appear inSpider-Man 4. The characters and the rest ofthe world forgot who Peter Parker wasdue to Doctor Strange’s spell, with Holland’s Marvel hero deciding not to remind MJ of their time together to keep her safe. Due to that, while Peter could bump into her in the upcoming MCU movie, MJ playing a major role would not make much sense. Zendaya also has a busy schedule in 2025 withDune: Messiah, explaining her reduced role.

Spider-Man Brand New Day Logo Poster

Spider-Man 4 Theory: Mary Jane And Michelle Jones Are Sisters

The MCU Could Go For Two Different Versions Of MJ At The Same Time

Zendaya’s MJ does not make it impossible for Sink to play the MCU’s Mary Jane Watson. After all, Marvel has made it very clear that the two are different characters, as Zendaya’s MCU role is Michelle Jones, and her closed-off persona is nowhere near Mary Jane’s outgoing personality. Even thoughMichelle received the MJ nickname Mary Jane is known for, effectively having her occupy the latter’s role in the MCU’s Spider-Man franchise, the two could co-exist. That is the driving force of a newSpider-Man 4theory shared on Reddit by userRandonanon4774that explains how they could be sisters.

When MJ was questioned by the Department of Damage Control inSpider-Man: No Way Home, it was revealed that her full name was Michelle Jones-Watson. However, Zendaya’s character claims she does not go by Watson. TheSpider-Man 4theory pulls from the comics, remembering that Mary Jane has a complicated relationship with her father in them. The MCU could do a version of that, withZendaya’s MJ not keeping in touch with her father, who lives somewhere else with her estranged sister, Sink’s Mary Jane. When Peter tries to look up MJ afterAvengers: Doomsday, he finds Mary Jane instead.

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How Spider-Man 4’s Possible Mary Jane Debut Is Better Through The Theory

The MCU Needs To Handle The Mary Jane Question Carefully

The theory is not the only way Sink could be introduced as Mary Jane. The character could come from another universe, given how the MCU’s Multiverse Saga still rages on, andSpider-Man 4will be released between the next two Avengers movies. Mary Jane Watson could also simply come from Earth-616, making her and Zendaya’s MJ two different characters with no relation besides the MJ nickname. Zendaya has had to face some nasty comments over the years due to her playing the MCU’s MJ, so introducing the “real MJ” now would not be a good look.

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Avengers 5 Concept Poster

Spider-Man 4

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Even though she is called Michelle Jones, and her personality is nothing like Mary Jane’s, it is clear that Zendaya’s MJ has effectively served in the iconic character’s role in the MCU’s Spider-Man franchise. As such, if Sink is to play Mary Jane Watson, then putting a new twist to her story that ends upadding more depth to Zendaya’s MJis the way to go. The theory that Michelle Jones and Mary Jane are sisters is perfect due to that, and Tom Holland’sSpider-Man 4has the chance to make Sink’s casting a major moment for MJ’s character development.

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Spider-Man: Brand New Day

Cast

Spider-Man: Brand New Day is the first sequel to the MCU’s Spider-Man trilogy starring Tom Holland as the titular wall-crawler. After wiping his identity from the public’s memory in Spider-Man: No Way Home, Peter Parker continues his crime-fighting adventures without the aid of Iron Man technology or the support of his former allies.