Rose Leslie is Ygritte
According to The Hollywood Reporter , Downton Abbey actress Rose Leslie has nabbed the role of Ygritte. In the A Song of Ice and Fire book series by George RR Martin, Ygritte is a wildling woman and spearwife who becomes a love interest for Jon Snow (played by Kit Harington).
In the first series of Downton , she played Gwen, a housemaid with dreams of moving onto better things. Personally, SFX would regard Game Of Thrones as a better thing.