Mackenzie Phillips (born November 10, 1959) is an American actress. She is the daughter of seminal folk-rock musician John Phillips of The Mamas and the Papas and his first wife Susan Adams. Her best-known roles include Carol Morrison in the film American Graffiti, Julie Cooper Horvath on the sitcom One Day at a Time, Molly Phillips on Disney Channel’s supernatural series So Weird, and Barbara "Barb" Denning in Orange Is the New Black.