'Hairspray' Turns 15! Nikki Blonsky, Director Adam Shankman Reveal Secrets from Set of Iconic Movie Musical

Hairspray's still got the beat!

Adam Shankman's sparkly, barrier-breaking movie musical, turns 15 on Wednesday.

A film adaptation of the 2002 Broadway musical of the same name (itself based on John Waters' 1988 movie starring Ricki Lake), Hairspray follows plucky teen Tracy Turnblad as she chases big-star dreams while fighting for racial equality amid the turbulent civil landscape of 1960s Baltimore.

Featuring a cast of recognizable faces like James Marsden, Michelle Pfeiffer, Queen Latifah, Christopher Walken, Zac Efron, Amanda Bynes, Allison Janney — and, of course, John Travolta in drag as Edna Turnblad — the film also familiarized the world with newer talent, including Elijah Kelley, Brittany Snow and Nikki Blonsky in the lead role of Tracy.

To celebrate Hairspray's crystal anniversary, PEOPLE spoke with star Blonsky, 33, and director Shankman, 57, about some behind-the-scenes tidbits even the biggest, blondest and most beautiful fans might not know.

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The entire cast still keeps in touch

Blonsky tells PEOPLE she still has a close relationship with onscreen mom Travolta, 68, and has reconnected with several other Hairspray cast members over the years, including Snow, 36, "a couple summers ago at the Nantucket Film Festival." She reveals, "We both just screamed because we just were so happy to see each other and I love her."

"And I had spoken to Elijah a couple of times and he is just always one of my favorite people that I've ever worked with," Blonsky says. "He's so fun, and nobody has a sense of humor like that guy. He is the prankster of all pranksters. So I love him as well."

Shankman still keeps in touch with many of the actors as well. He tells PEOPLE, "I was just with Marsden doing Disenchanted [the sequel to 2007's Enchanted, which Shankman's directing], so that was that. I just got a text from Latifah. I talked with John Travolta recently. Michelle, I'm having dinner with soon. Brittany Snow, I just talked to. Nikki, I've been in touch with. I haven't talked to Amanda. Zac, I talked to about a year ago when he was in Australia. I had an exchange with Elijah recently ... he had just gotten a job that I was super proud of him [for]."

"So we just get in touch with each other, give each other virtual love. Some of us see each other, but truly, if you look at everybody's lives, we're super busy," Shankman adds. "So we don't see each other. Somebody would have to try to put a gathering on the books for us to do that."

Asked if he'd be down for an in-person reunion, Shankman says, "If they get a screening at the Hollywood Bowl or at the [Hollywood Forever] Cemetery or something like that, I would try to get out as many people there as I could, but people are all over the place working. Everybody's booked and blessed. I'm super happy for everybody."

Nikki Blonsky and Zac Efron were "inseparable," even when not filming

Blonsky says she "had an absolute blast" working with Efron, 34, who played Tracy's dreamboat love interest Link Larkin in the film.

"From the minute we met, we were like buds — we were inseparable," she continues. "When we weren't dancing together, we were going out to dinner. We were just always hanging out. Even on our days off, he would call me and be like, 'What are you doing?' I'm like, 'I'm going to the mall.' He'd be like, 'I'm coming.' We always had things to do. Baseball games. We just had a lot of the same interests, and truly loved being around each other."

Blonsky says her mother "always kept an eye out for Zac and looked after him as well," as she was with Blonsky during filming. "We were kind of like a little family," she shares.

As for whether sparks flew between her and Efron in real life, "The chemistry was definitely Tracy and Link for sure," says Blonsky, who came out in 2020. "I guess we sold it pretty well but we've always just been, while we were making the movie, great friends, and he is somebody who I will always appreciate that I had a chance to work with because he is a wonderful actor and a very sweet, loving soul."

Nikki Blonsky was "at a loss for words" when she first met John Travolta

Blonsky's "favorite memory" from filming, she says, "is the day [she] met John for the first time." She was extremely nervous to come face to face with the iconic actor, as she "was all sweaty" from dance rehearsals.

"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 looked at me and I looked at him and that was the first time in my life I was just speechless," she recalls. "I was at a loss for words."

She was immediately put at ease as Travolta "looked at me, opened his arms and said, 'Come to Mama.' "

"From that minute on, I absolutely fell in love with him," Blonsky raves. "I always say Hairspray has been the greatest blessing of my life. But I think my favorite blessing that's out of Hairspray is my relationship with John. It means so much to me. We stay in touch and he has always been there, like an extra parent, if I need advice. I just cherish him."

RELATED VIDEO: Three Generations of Hairspray Stars Compare Leading-Man Makeout Stories

The cast had a themed dinner party every week during rehearsals

Every Tuesday night during rehearsals, the entire cast, including 65 dancers, would gather at Shankman's house that he'd rented for the entirety of their months-long shoot in Toronto for a "themed dinner party," he tells PEOPLE.

"If it was Mexican, I'd hire a mariachi band, or if it was Italian … I don't remember all the different things that we did, but it was always a themed thing, [we] fed everybody, and then we'd all watch So You Think You Can Dance, before I was on [as a judge]," Shankman says.

John Travolta couldn't stop shooting once in costume or else he'd "fry" in his latex suit

Getting in costume as Edna was no easy feat for Travolta — in fact, a timer started ticking as soon as he put on all the required layers because "once he walked on stage, we could not stop shooting because if we stopped, he'd fry," Shankman says.

"We'd have to pump air conditioning under the dress every time we'd stop," he continues. "And it was even difficult for sitting. So it took five hours for him to get in that drag, and then once he was in, it was like, 'Go, go, go.' You just had to literally never stop in order to get your days."

According to Blonsky, "pro" Travolta was "so incredibly light on his feet" and made the dancing "look effortless."

"He was so nice to every single cast member, every extra, every person on set," she says. "And that is what set the tone for basically the amazing experience we all had because everybody was just so excited every day to show up, to work, put on our costume and work with John."

The original film's creator, John Waters, said he was proud of the remake

Shankman admits he was nervous to touch a story as iconic as the one first tackled by Baltimore native Waters, now 76, in the 1988 film, which Waters directed, wrote and co-produced.

But Waters — who had a cameo as the "flasher who lives next door" during the 2007 film's opening "Good Morning Baltimore" sequence — gave his full stamp of approval.

"Probably the greatest moment for me in making it was when I got an email from John Waters after he watched it that just said, 'Dear Adam, I just saw your version of Hairspray. You've made me the proudest grandfather on the face of the earth. Love you, John,' " recalls Shankman.

"I almost died," he adds. "'Cause that's all I wanted to do, was make John proud, so that was a really big deal."

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