John Travolta made a surprise appearance at Friday night’s “Grease” sing-a-long at the Hollywood Bowl dressed as his iconic drag racing, hip swinging 1950s bad boy Danny Zuko. “Tonight at the Hollywood Bowl,

"Grease," based on the hit 1972 Broadway musical of the same name, follows Danny, a local bad boy, and Sandy (Olivia Newton-John), a wholesome high school transfer student from Australia, as they reunite at Rydell High School after meeting at the beach over the summer.

Fans at the 'Grease' Sing-A-Long screening at the Hollywood Bowl last night got a surprise when the original Danny Zuko strutted out onstage.