She is famous for playing stab-happy (her sister gets raped and one of her brothers is last seen with Anne Frank so it seems to run in family) teenager in award-winning shark-jumping medieval fantasy show Game of Thrones and for appearing as Ashildr in Doctor Who and Me in Clara & Me.
Also for her unusual features (politically correct code for "being rather plain").
She also starred in movie Cyberbully in which she was cyberbullied, and in another movie called The Falling in which she was repeatedly falling (Also, banged her brother because this is what happens when you are raised by a single parent in the Sixties).
She is scheduled to appear in series 9 of Doctor Who in capacity unknown. Since she is too young to play Rani or Romana, she is most certainly playing returning Jackson Lake, Victorian schoolteacher who is led to believe he is The Doctor due to malfunctioning Cybermen technologies.