By Mark Kennedy, Entertainment Writer

NEW YORK (AP) --

While many of John Gallagher Jr.'s peers went to college, he didn't. His university became "Spring Awakening."

Gallagher spent much of what would have been his prime college years — from 20 to 23 — starring in the original, envelope-pushing Broadway show that musicalized teen angst.

"It was an education," he said. "It was a social education. It was a professional education and a personal education in so many respects."

Gallagher recently got a chance to go back to school by reuniting with the cast for the first time in 15 years during a one-night benefit concert.

The new documentary "Spring Awakening: Those You've Known" airing Tuesday on HBO and HBO Max captures that concert and adds interviews, candid moments and home movies, as well as performance footage from the original 2006 Broadway show, often beautifully melting into the benefit concert.

"It's been profound to be together again and look back," said Gallagher, who went on to have Broadway roles in "American Idiot" and "Jerusalem" and on TV in "The Newsroom."

Filmed in just five days and edited in a mater of weeks, "Spring Awakening: Those You've Known" follows four major plot lines: the musical itself, its 2006 road to Broadway, the reunion 15 years later in 2021 and the special relationship between breakout stars Jonathan Groff and Lea Michele.

"This was also an opportunity to uncover what 'Spring Awakening' really was and still is today — an unapologetic examination of teenage angst and the timeless desire to find acceptance for who you are and what you are going through," said Dave Sirulnick, of RadicalMedia, which produced the documentary.

Set in provincial 19th-century Germany but using modern rock songs, "Spring Awakening" tells the story of a group of teenagers trying to come to terms with life and their sexuality. It won eight Tony Awards in 2007, including for best musical.

"They were in this lightning-in-a bottle moment together," said documentary director Michael John Warren. "And it shaped who they were, and they were shaping who they were in real time."

The show is beloved in the musical theater community for pushing the envelope in terms of staging and content, respected alongside other ground-breaking shows like "Rent" and "Hamilton."

"I think it was a complete break with tradition," says cast member Lilli Cooper, who has gone on to a Tony-nominated career in such shows as "SpongeBob SquarePants," "Tootsie" and who currently stars in "POTUS."

"I don't think I knew how transcendent this show really was when I was doing it every night. But now I look back and I truly believe that it has changed the landscape of Broadway and has changed the landscape of musical theater."

The documentary shows just how close to disaster the edgy musical was back in 2006 after it had made the jump from an off-Broadway venue with 300 seats to a Broadway theater with 1,100. There were long lean months before Tony nominations came out, helping to propel the show to pop culture success.

"We remember looking out into the audience and not seeing hardly anybody. And that was for months and it was scary. Every time we had a meeting with our producers, we thought it was going to be our closing notice. And so to go from that to kids sleeping outside of the stage door to get tickets is just so wild," said Cooper.

The cast of the original show was loaded with actors like Groff, Michele and Cooper, as well as Jennifer Damiano, Gideon Glick, Lauren Pritchard and Krysta Rodriguez, who have each gone on to fame in TV, film and stage. Groff would go on to earn a Tony nod with "Hamilton," and Michele became a superstar with "Glee."

Groff and Michele grew particularly close, learning about themselves as they performed a show about kids learning about themselves. In the film, Michele reveals that she once allowed Groff to inspect her private parts since he was unfamiliar with female anatomy. Returning to the show as a grown-up was a trip, she said.

"I think we understood this material a lot more. I think it meant different things to us now as adults," said Michele." "It's very different listening to the words of this show and understanding what it means from that point of view."

The musical — adapted from a 19th-century play by German playwright Frank Wedekind — is frank in its portrayals of incest, abortion and suicide. It is intended partly as a warning that teens need good information about sex to avoid tragic mistakes.

"These are the kind of messages that were relevant in 1891 when the original text was written. They were relevant in 2006 when the show was mounted on Broadway, and they're painfully relevant in 2022 and in some ways even more relevant," said Warren.

Cast members revealed that young adult fans would wait outside the theater doors after the show to tell them how much the work meant to them or slip them notes saying they finally felt understood.

"That's why you do it," said Gallagher. "You do it with the hope that you will change somebody's life the way that pieces of art have changed mine — being able to be part of something that wasn't just a kind of good time, but also made a real difference in young people's lives."

The reunion was more than a little surreal for Cooper, who had been a teenager during the original run. Like Michele, she returned as a new mother — with a new perspective on "Spring Awakening."

"I completely look at it through a different lens now as a mother," she said. "When I was a teenager, I really thought the show was about these teenagers. And to a certain extent it is. But now I look at it through the lens of being a parent, and I really see how this story is actually about the lack of understanding between generations."

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