John Travolta & Olivia Newton-John Revive 'Grease'

John Travolta and Olivia Newton-John gave a bunch of fans an evening that will trigger jealous rages across the country … a “Grease” revival!!!

Olivia and John were front and center Friday night at the Meet n’ Grease Sing-Along at the Coral Sky Amphitheater in West Palm Beach, Florida.

They recreated their iconic characters, Danny Zuko and Sandy Olsson. And they both really look good, and sound really good.

So check out the video … 71-year-old Olivia sings “Hopelessly Devoted to You,” and John sings “Sandy,” and then joins the male chorus in “Greased Lightenin’.”

Olivia, as you know, has struggled in her battle with cancer, and she’s always said John has been there for her during tough times.