The Hollywood Bowl’s Grease sing-a-long event was automatic, systematic, hydromatic and grease lightning — thanks to a very special cameo from film star John Travolta. “Tonight at the Hollywood Bowl,

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.

Grease star John Travolta shocked fans by strolling out dressed as Danny Zuko at a sing-a-long event for the hit 1978 film in Los Angeles. The 71-year-old actor starred as the charismatic T-Bird opposite Olivia Newton-John as angelic Sandy Olson in the hit musical.