Olivia is girl who has a crush on Luke Dunphy who is mentioned in "Planes, Trains and Cars".
Luke is talking with Leon and his other school parterns about the soccer game they have just played. Leon tells Luke that Olivia always watches Luke when he plays. Luke believes that she is in love with soccer, but she has actually a crush on him. Phil then asks Claire if she knows that there's a girl with a crush on Luke, Olivia, and Claire tells him that she already knew it.