Marvel Studios chief Kevin Feige has explained why the studio went to great lengths to hide Sadie Sink's role as Jean Grey in Spider-Man: Brand New Day, despite widespread online speculation correctly identifying the character months in advance. Feige said the secrecy was designed purely to preserve the opening weekend experience for audiences, given the character's significance to the wider Marvel Universe and her expected future role in the franchise.

Sink was cast in the film back in March 2025, with reports at the time already pointing to a Jean Grey role, yet Marvel maintained silence throughout marketing before finally confirming it after release. In the film she plays the villain, using telepathic powers to control MJ, the Hulk, the Punisher and ordinary New Yorkers. The secrecy echoed Marvel's approach to Spider-Man: No Way Home's cameos, and comes as Brand New Day has enjoyed a huge box office debut, taking around $930 million worldwide in its opening weekend since its 31 July premiere.