Chloe Grace Moretz will star in Brain on Fire, the adaptation of Susannah Cahalan’s best-selling memoir being produced by Charlize Theron.
Dakota Fanning was due to topline the indie, being directed by Gerard Barrett, but bowed out due to scheduling issues.
The story chronicles a young woman’s sudden descent into insanity following a mystery illness.
Thomas Mann is already on board the project, which is being financed and produced by Foundation Features. Theron’s Denver & Delilah banner is also producing.
Moretz showed her dramatic chops to Theron when the two starred together in the thriller Dark Places, which A24 is releasing Aug. 7.
Moretz — repped by WME and Jackoway Tyerman — was also seen with Denzel Washington in The Equalizer and last year toplined If I Stay, New Line’s adaptation of the Gayle Forman novel.
Updated June 26, 2:00 to reflect that Will Poulter is no longer part of the cast.