The movie Grease has made over 395 million worldwide since it's release in 1978 due largely in part because of John Travolta and Olivia Newton-John. They perform 'You're The One That I Want', one of the main songs from the film, many years after the release of Grease live, here in perfect Rydell High School fashion. They are just a lot older.
Grease was originally released in 1978 but in 2002 Paramount released Grease on DVD and held a release party in Hollywood which is when Travolta and John took the stage to sing