EXCLUSIVE: Thomas Mann and Jenny Slate are in talks to join Dakota Fanning in Brain On Fire. Glassland’s Gerard Barrett is directing his scripted adaptation of the Susannah Cahalan’s bestselling memoir Brain On Fire: My Month Of Madness, with Fanning playing the author during a terrifying and sudden descent into insanity as the result of a mysterious illness.

Image (3) thomas-mann__131030173918-143x150.png for post 623376Jenny Slate FX PilotCharlize Theron, Beth Kono and AJ Dix are producing for Denver and Delilah Films, and Rob Merilees for Foundation Features. The pic shoots July in Vancouver and New York, and Mister Smith Entertainment is handling sales. Mann, who broke out of Project X, next stars in Me And Earl And The Dying Girl, which drew raves in its Sundance premiere and will be released by Fox Searchlight this summer (he also starred in the Sundance preem The Stanford Prison Experiment). He’ll play Cahalan’s boyfriend. Slate broke out in Obvious Child, and the former Saturday Night Live castmember is starring in the FX series Married.