The Australian actress, 34, is said to be set to play Emma Frost in Marvel Studios' long-awaited reboot of The X-Men.
Famed for her role in Ready or Not, Variety reports Weaving is set to take on the role of the powerful telepath, a character whose journey in Marvel Comics has seen her evolve from one of the X-Men's most formidable villains into one of their most complex heroes.
The casting news follows Marvel Studios' major Hall H presentation at San Diego Comic-Con last weekend, where the studio also announced that Ryan Gosling will play Ghost Rider and revealed Alien: Romulus star David Jonsson has been cast as the new Black Panther in Black Panther 3.
The announcements come as Marvel looks to rebuild momentum after Captain America: Brave New World and The Fantastic Four: First Steps underperformed at the box office, while Spider-Man: Brand New Day is expected to reverse the trend after opening to record-breaking figures. Sony distributes the Spider-Man films.
Weaving, who has become one of Hollywood's leading scream queens thanks to films including Ready or Not, The Babysitter and Scream VI, most recently starred in Ready or Not 2: Here I Come and Over Your Dead Body.
She has also appeared in the Oscar-winning drama Three Billboards Outside Ebbing, Missouri and the comedy sequel Bill and Ted Face the Music.
Marvel's reboot of The X-Men will be directed by Jake Schreier, following his work on Thunderbolts.
The film marks the studio's first standalone X-Men project since Disney completed its acquisition of 20th Century Fox in 2019, bringing the mutant characters fully under the Marvel Studios banner after years outside the MCU.
Marvel is undergoing a wider overhaul of its upcoming slate following the Comic-Con showcase, as the studio prepares to expand its mutant storylines after years of anticipation from fans.