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Sadie Sink’s surprising Spider-Man 4 casting announcement supports my theory that the Stranger Things star is playing the X-Men hero Jean Grey in the MCU. The MCU’s Spider-Man 4 is advancing in development faster than other MCU sequels, and a lot may be at stake, both for Tom Holland’s Spider-Man journey and the MCU as a whole. Given that the chances of Zendaya’s MJ and Jacob Batalon’s Ned Leeds returning for the MCU’s next Spider-Man movie are low after Spider-Man: No Way Home‘s ending, it’s likely that Holland’s Peter Parker will be joined by new friends in Spider-Man 4.

Sadie Sink Has Been Cast In Spider-Man And Speculation Points To Her Playing Jean Grey

Sadie Sink Is The First Big Name To Join The MCU For Spider-Man 4

Custom image by Debanjana Chowdhury

On March 12, 2025, Deadline reports that Sadie Sink has joined Spider-Man 4‘s cast. Before Sink’s official casting was reported, it was heavily speculated that she would be playing a major MCU character soon, with the most popular theories revolving around the X-Men member Jean Grey. While these used to be fan theories, Sadie Sink’s Spider-Man 4 casting suggests that they may have had a solid basis all along.