John Travolta Sang Grease Songs on Hairspray Set

John Travolta brought greased lightnin' to the set of Hairspray.

In honor of the movie musical's 15th anniversary, Nikki Blonsky tells PEOPLE that the actor, now 68, "surprised" the cast by performing hit songs from his 1978 film Grease during a break on set.

"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 recalls.

Blonsky, 33, reveals that she couldn't help but join in on the fun. She adds, "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.' "

The Huge alum says the experience was "truly one of the highlights of my life."

Blonsky recalls her first meeting with Travolta left her in awe after director Adam Shankman encouraged her to introduce herself in the middle of dance rehearsals.

"Adam Shankman came and knocked on our rehearsal door and he looked at me and he goes, 'It's time.' And I said, 'What?' He goes, 'John's here. You've got to go meet him. Let's go,' " she says. "I was like, 'No, no, no, no, I'm sweaty. I can't meet him now.' And he was like, 'You have to, we've got to go.' ''

She continues, "I'll never forget, he was in the wardrobe department. John was sitting there on one of the couches and I walked in and he took one look at me and I looked at him and that was the first time in my life I was just speechless. I was at a loss for words."

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Blonsky says Travolta, who played her onscreen mother Edna Turnblad in the movie, immediately eased her nerves.

"He looked at me and he opened his arms and he said, 'Come to mama.' And from that minute on, I absolutely fell in love with him," she says. "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."

She adds, "It means so much to me. We stay in touch and he has always, always been there like an extra parent if I need advice and I just cherish him."

Hairspray is available to own on Blu-ray and digital now.

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