Katherine Evelyn Anita Cassidy (born November 25, 1986); is an American actress and director. She is best known for her role as Laurel Lance on the television series arrow. Following several minor television roles, she came to attention as a scream queen after starring in the horror films When a Stranger Calls (2006), as Kelli Presley in Black Christmas (2006) and as Ruby in the third season of the horror series Supernatural (2007–08). Following a supporting role in the action film Taken (2008), Cassidy played leading roles in the mystery horror series Harper's Island (2009) and the remake of the drama series Melrose Place (2009–10). She starred as Kris Fowles in the slasher film remake A Nightmare on Elm Street (2010) and had a recurring role as Juliet Sharp during the fourth season of the teen drama Gossip Girl (2010–12).