Sadie Sink’s Big Sister in “Spider-Man: Brand New Day” Is 8 Years Younger Than She Is

Audiences walking out of Spider-Man: Brand New Day are preoccupied with a casting choice that the movie never mentions: Sadie Sink’s older sister is played by an actor who is eight years younger.

Sink, 24, stars as Jean Grey in the Marvel-Sony production, wrapping up speculation about the role that was kept under wraps throughout the marketing campaign. British actress Olivia Booth-Ford, 16, is Sara Grey, Jean Grey’s older sister, whose kidnapping by the Department of Damage Control drives much of the movie’s plot.

While the casting choice of an older character played by a younger actor opposite a younger character played by an older one has remained unnoticed by the audience until the credits and comparison of birth dates on social media sites, the responses on the web have generally been positive, as many fans applauded the performances and how convincingly the siblings were portrayed despite the age gap.

Booth-Ford, better known as Janet Hodgson in Apple TTV+’sThe Enfield Poltergeist and Leoni Tennant in the BBC series Waterloo Road, appears mostly in flashbacks that explain the sisters’ past. Both of the Grey siblings possess telepathic powers as children, but are abandoned by their mother and manage to survive through foster care until Sara is kidnapped.

Sink, who first came to prominence as Max Mayfield in Netflix’s Stranger Things, was announced to be joining the cast of the movie in March 2025, without any role mentioned. She becomes the third actress to portray Jean Grey in live action, after Famke Janssen in the original X-Men trilogy and Sophie Turner in the 2016 and 2019 films.

The practice of casting actors younger than their characters’ ages is common in the film and television industry, where availability, on-screen chemistry, and labor laws often take precedence over realistic casting. While it is relatively common for productions to cast actors in their twenties to play teenagers, the reverse of casting minors as the older sibling is relatively rare.

Sink’s Jean Grey is set to appear in Avengers: Secret Wars, which is scheduled to be released in December 2027, and in an X-Men movie, directed by Jake Schreier.

Spider-Man: Brand New Day is currently in theaters.