In addition to Lily James role as the great-niece of Maggie Smith in Downton Abbey, she held a leading role in Fast Girls (2012) and starred in Wrath of the Titans (2012). In 2011, she played the character Poppy in the television series Secret Diary of a Call Girl opposite Billie Piper. She is the granddaughter of actress Helen Horton who held a role in the 1979 science-fiction horror film Alien.