In 1978 the Grease soundtrack became a phenomenon. Its good-natured combination of doo-wop and early rock ‘n’ roll is infectious and charming, due in no small part to John Travolta and Olivia Newton-John’s charismatic, engaging performances. They sing the majority of the tracks including “Summer Nights,” “Hopelessly Devoted To You,” “You’re the One That I Want,” “Greased Lightnin'” and more.