John Travolta sang 'Grease' songs on the set of 'Hairspray' to pass the time, says costar

• Nikki Blonsky recalled when John Travolta started singing "Grease" songs on set.
• "Zac [Efron] and I looked at each other and gasped," Blonsky told People of when Travolta started singing.

John Travolta brought back the classics while on the set of the 2007 movie, "Hairspray."

In an interview with People for the movie's 15th anniversary, star Nikki Blonsky recalled what Travolta did once to pass the time.

"We were filming in Queen Latifah's music shop and all of a sudden we were on a break and one of the dancers yells out, 'John, give us a little Grease,'" she recalled, referencing the iconic 1978 musical movie Travolta starred in.

"Zac [Efron] and I looked at each other and gasped. We were like, 'Oh my gosh, is this going to happen?' And yeah, he sat there on the couch and he did a little 'Summer Loving' and then him and I did 'You're the One That I Want.'"

In "Hairspray," which was the big-screen adaptation of the 2002 Broadway musical comedy, Travolta played the mother of Blonsky's Tracy character.

Travolta became a huge star starring opposite Olivia Newton-John for their portrayals of Danny and Sandy in "Grease," which was a movie adaptation of a 1971 musical.

However, despite being a legend, Blonsky told People that Travolta was very down to Earth when they first started working. Especially when Travolta was in full costume as her mother, Edna.

"He looked at me and he opened his arms and he said, 'Come to mama,'" Blonsky said. "And from that minute on, I absolutely fell in love with him. I always say 'Hairspray,' it has been the greatest, greatest, greatest blessing of my life. But I think my favorite blessing that's kind of out of 'Hairspray' is my relationship with John."