John Travolta, who starred as 'Grease' bad boy heartthrob Danny Zuko, crashed the Hollywood Bowl's sing-along event Friday. He surprised the audience and "Grease" co-stars alike.

John Travolta's Danny Zuko reemerged at the Hollywood Bowl, 47 years after the star portrayed the Rydell High T-Bird in 'Grease' the movie.

John Travolta gave "Grease" fans the thrill of their lives when he dressed up as Danny Zuko for a surprise appearance at a screening of the hit 1978 movie musical. The 71-year-old actor shared a pic on Instagram that showed him wearing a leather jacket and a slicked-back pompadour to make a cameo at a June 27 "Grease" sing-along at the Hollywood Bowl in Los Angeles.