John Travolta Mourns His Iconic 'Grease' Co-Star Olivia Newton-John

John Travolta pays tribute to Olivia Newton-John. His iconic 'Grease' co-star died on Monday. She was 73. Following the musical's success, the actors reunited for 'Two of a Kind' in 1983. Olivia and John opened up to ET over the years about their undeniable on-screen chemistry.