Grey's Anatomy getting ready for Campbell's screams in December.

Grey's Anatomy announced adding actress Neve Campbell to its cast for at least two episodes where she plays Dr. Derek Shepherd's sister who helps him after the plane crash accident.According to Hollywood Reporter; Campbell will start appearing in December episodes but it's not announced which of Derek's four sisters she will play.It's worth mentioning that Campbell and Patrick Dempsey (Dr. Shepherd) worked together in "Scream 3".