Anna Stern is a fictional character on the FOX television series The O.C., portrayed by Samaire Armstrong. Initially intended to appear in only one episode, she was brought back at fan request for several episodes of the first season. After a successful run, Melinda Clarke and Rachel Bilson were added to the main cast in the thirteenth episode, while Samaire Armstrong wasn't despite the regular appearance of her character. She appears on the back of the Music from the OC: Mix 1 album with the main cast of season 1.In the episode of season 3 "The Party Favor" Anna is saying to Seth and Summer: "I'm gonna go. I fly back tomorrow, but I'll see you both in Providence." So Anna is a student at Brown University, but she is offscreen. In the booklet of the 'Mix 5' CD most cast members leave messages to each other including "Hey guys-see you soon! Missing you in Pittsburgh-Anna"