Actress to return to her period drama roots.

Deadline is reporting that 18 year-old Irish star Saoirse Ronan (‘The Host,’ ‘Hanna,’ ‘Atonement’) is attached to star in the period drama ‘Testament of Youth,’ an adaptation of Vera Brittain’s First World War memoir.

Scripted by Juliette Towhidi (‘Calendar Girls’), the period drama traces Brittain’s experiences as “a disillusioned nurse during the war and the beginning of her career as a journalist and pacifist.”

The film, which is currently without a director, will be a co-production between Heyday Films and BBC Films.