Cooke - who recently starred as Christopher Eccleston's daughter in BBC drama Blackout - has been cast as a character named Emma, Deadline reports.
Emma - described as "bright" and "eccentric" - has a life-threatening disease and so is determined to make the most of life.
Cooke's other forthcoming roles include Hammer horror film The Quiet Ones and the BBC's Halloween drama The Secret of Crickley Hall.
Charlie and the Chocolate Factory star Freddie Highmore will play a young Norman Bates in Bates Motel - the role made famous in Alfred Hitchcock's 1960 horror Psycho by Anthony Perkins.
Vera Farmiga (Source Code) has been cast as Norma Bates, Norman's "passionate and compelling" mother.
Bates Motel expected to premiere on A&E in 2013 with a ten-episode first season.
> Psycho TV prequel Bates Motel in development at A&E
> A&E orders Alfred Hitchcock's Psycho-inspired series Bates Motel
Watch a trailer for Psycho below: