Due to scheduling conflicts, Dakota Fanning (Now Is Good) has bowed out from starring in the adaptation of the best-selling memoir Brain on Fire and Chloe Grace Moretz (If I Stay) has stepped in to fill the role, according to The Hollywood Reporter. Fanning had been attached to the film for over a year, and the quick casting switch was made just before the film is set to begin shooting this July in Vancouver. 

Moretz will now be playing the role of Susannah Cahalan in her harrowing story of a mysterious and whirlwind neurological disorder. The film will follow Susannah as she experiences a sudden descent into insanity following the unexpected illness. Thomas Mann (Project X) also recently signed on to play Susannah’s boyfriend Stephen, as did Jenny Slate (Obvious Child) for an unknown role.

Gerard Barrett adapted the screenplay and will also direct and produce alongside Charlize Theron under her Denver and Delilah banner. Barrett’s second and most recent feature film, Glassland, won the Sundance Film Festival‘s Special Jury Prize in the World Cinema – Dramatic category.

Although the re-casting may seem like a hasty turnaround, producer Theron is already familiar with Moretz after co-starring with the young actress in this summer’s dramatic thriller Dark Places, a Gillian Flynn adaptation. Moretz also has room in her upcoming schedule to take on the role, as she has recently finished filming November Criminals with Ansel Elgort (The Fault in Our Stars) and The 5th Wave with Nick Robinson (Jurassic World), giving her a small window before she begins promo tours for the two movies.