Kit Harington has signed on to reunited with his Seventh Son co-star Alicia Vikander in Testament of Youth for BBC Films. Alicia Vikander replaced actress Saoirse Ronan late last year.

The story is adapted from Vera Brittain's 1933 autobiography, which chronicles her experiences during World War I. She put her studies at Oxford on hold to become a nurse in the war, which claimed the lives of both her fiance and brother. After the war ended, she tried to get her life back on track, but found herself as part of a lost generation. She later returned to Oxford to become a feminist and a writer. Alicia Vikander is portraying Vera Brittain, with Kit Harington playing her fiance.

James Kent, who most recently directed three episodes of The White Queen for Starz, is directing from a script by Juliette Towhidi (Calendar Girls). David Heyman (Gravity) is producing, although it isn't known when shooting will begin.

RELATED: Testament of Youth Lands at Sony Pictures Classics

Kit Harington is best known for playing Jon Snow in the hit HBO series Game of Thrones. He will next be seen on the big screen in Pompeii, which hits theaters February 21.