Inside the Disney Channel’s brutal fame factory and how far Zac Efron, Demi Lovato and Selena Gomez really had to go to win roles: book

Zac Efron was not the obvious choice to star in “High School Musical,” the 2006 Disney Channel movie about a lovestruck basketball player who auditions for his school’s musical theater production. 

The then-17-year-old actor had a gap between his teeth. He had floppy hair. He was not a singer. He did not live in Los Angeles, but in the laidback college town of San Luis Obispo, in central California — a world away from Tinsel Town.

“He didn’t have any of that Hollywood polish at all,” casting director Natalie Hart tells author Ashley Spencer in the dishy new book, “Disney High: The Untold Story of the Rise and Fall of Disney Channel’s Tween Empire” (St. Martin’s Press, out now). “It’s sort of what endeared him to us, because he was just a good guy and a lovely kid.”

The “High School Musical” cast included Corbin Bleu (from left), Monique Coleman, Zac Efron, Vanessa Hudgens, Ashley Tisdale and Lucas Grabeel. Handout

But Disney Channel execs wanted a leading man with pearlier whites and a more “athletic build.”

Spencer writes that Efron jumped through all kinds of hoops to get the part. He underwent a makeover to fix his gap-toothed grin and mop of hair. Then he endured sessions in the recording booth laying down his vocals for the soundtrack — only to have his voice swapped out of the final film. 

“After everything was recorded, my voice was not on [the songs],” Efron told the Orlando Sentinel in 2007. “I was not really given an explanation.”

Efron was shocked, and hurt. He and his HSM peers “had all been cast as triple threats,” Spencer writes. “Now, Zac was the only one deemed unsuitable to fulfill his singing duties . . . [Disney had put him] in an incredibly awkward position.”

The Disney Channel debuted 1983 as a niche premium cable add-on aimed at families, but it didn’t develop into a tween powerhouse until the early 2000s. 

“High School Musical” star Corbin Bleu (right, with Efron) said the teen actors were treated like adults on set. “We were pushed to our max,” he recalled. Disney Enterprises A dishy new book looks at what was happening behind-the-scenes on beloved Disney Channel shows.

By then, it was must-see TV for young millennials coming of age. They reserved Friday nights to watch the latest “DCOM” (Disney Channel Original Movie), and idolized its teen stars, such Hilary Duff (a k a “Lizzie McGuire”), Miley Cyrus (a k a “Hannah Montana”) and Raven-Symoné (the star of “That’s So Raven”).

But while the cable channel churned out wholesome family entertainment that empowered its young audience, its adolescent actors often struggled behind the scenes. 

“That’s the thorny paradox of the Disney Channel story,” Spencer writes. “As the network’s heyday programming brought comfort and joy to millions of tender viewers, the coterie of young stars appearing on screen were having to prematurely navigate the pressures of very adult scenarios.”

“Even though we worked kid hours and everything was within those legal confines, we were still treated as adults,” HSM actor Corbin Bleu tells Spencer.

“High School Musical” was shot in sweltering conditions.

The movie was shot on location at a Salt Lake City high school with no air conditioning during the height of the summer. The performers “sweltered under the production lights in the poorly ventilated gymnasium and classrooms,” only cooling off in front of portable AC units in the hallway during breaks, Spencer writes.

“We were pushed to our max,” Bleu says in the book.

After the success of “High School Musical,” the channel sent its young stars on a whirlwind media tour — eight- to 10-hour days answering questions from reporters with, several cast members told her, no media training — and planned a grueling 50-plus-date concert tour. Efron declined to go on the tour, since he didn’t actually sing in the movie.

“They worked us so hard, I mean, we didn’t really have days off,” Lucas Grabeel — who played a scheming theater brat in the movie — tells Spencer.

By the time Grabeel finished the tour and began filming “High School Musical 2,” he had to wear a back brace and knee braces due to injuries exacerbated by doing cartwheels night after night on stage. 

Like the old Hollywood studios of yore, the Disney Channel pumped out anodyne entertainment with cast of talented multi-hyphenates who could act, sing, dance and behave immaculately — generating millions and millions of dollars and good press for the company.

The channel frequently added a morals clause to its young stars’ contracts, saying they couldn’t behave in a way that would “degrade” themselves or “shock, insult or offend the community,” Spencer notes.

“Hannah Montana” star Miley Cyrus said she was making too much money for Disney to get days off. ©Walt Disney Co./Courtesy Everett Collection

Maintaining a squeaky image while working across multiple platforms was a pressure cooker for some teen and tween talent.

“Even for those who make it look easy while in the throes of the 360-degree circus that came with being a Disney Channel star, it was a years-long exhausting grind, the effects of which followed many into adulthood,” Spencer writes.

Miley Cyrus was 12 years old when Disney cast her in the sitcom “Hannah Montana” and signed her for a record deal simultaneously. The show — about a normal teenage girl who has a secret life as a pop star — made Cyrus a tween idol. 

“Hannah” aired from 2006 to 2011. During that time, Cyrus hustled.

“She filmed the show during the week, and on weekends and hiatuses did mini concert tours and appearances, filmed movies, attended media events, posed for photo shoots and recorded new music,” Spencer writes.

Cyrus co-starred on “Hannah Montana” with dad Billy Ray Cyrus. Disney General Entertainment Content via Getty Images

That didn’t include the hours and hours she spent volunteering with the Make-A-Wish Foundation, hand-delivering presents, recording personalized videos and giving backstage tours to children battling critical illnesses and their families.

“Nobody knows how much was on her shoulders and how much she had to carry for a long time,” executive producer Steven Peterman tells Spencer. “There were times when Miley was being pulled in three directions. One was the necessities of filming the show. One was the Disney appearances and recordings. And once she blew up and had her separate management, they had their own agenda . . . And her family was a little nervous about saying no to people because nobody knew how long this was going to last.” 

Cyrus put it more bluntly on Joe Rogan in 2020.

“I didn’t get recovery days,” said Cyrus. “That was not important for someone who was making so much capital for such a big corporation.”

Demi Lovato and Selena Gomez costarred in Disney’s “Princess Protection Program.” Disney Channel

Then there was Matthew Finley. The young actor fell and landed on his chin while doing a backflip while filming a musical number for 2010’s “Camp Rock 2.” Yet, according to Spencer, production bandaged his injury, touched up his makeup and had him keep performing, “periodically changing into fresh white shirts as blood seeped through his bandage.”

He eventually was rushed to the hospital to receive stitches, but he tells Spencer: “My safety was definitely disregarded.”

Selena Gomez and Demi Lovato first met on the set of “Barney & Friends” when they were 7 years old. The two Texas natives became best friends. Gomez landed a Disney Channel series — the Harry Potter-inspired “Wizards of Waverly Place — in 2006, and she constantly touted her pal Lovato to the network.

Lovato got her first break on the channel that same year, on a short-form series called “As the Bell Rings.” But when network executives heard the then 14-year-old sing, they decided she needed a bigger launching pad. In 2007, they booked her for a new musical movie (“Camp Rock”) and her own sitcom (“Sonny with a Chance”).

When network executives heard a 14-year-old Demi Lovato sing, they decided she needed a bigger launching pad. Disney Channel via Getty Images

Danny Kaplan, showrunner for “As the Bell Rings,” warned the network that he was worried about Lovato’s mental health, noticing her restrictive eating habits and her unhappiness on set.

“Honestly, there were signs,” he tells Spencer. “But, I don’t think anybody really did much about it.”

Lovato and Gomez paired up in 2008 for the DCOM “Princess Protection Plan.” Yet Lovato had a hard time separating real life from the characters she played, said “Princess” director Allison Liddi-Brown.

Lovato, who was 15 or 16 at the time, broke down when she had to film a scene in which she gets bullied by other kids. “Shooting that really kicked up a lot of stuff from her past,” Liddi-Brown tells Spencer. 

Selena Gomez (left) and Demi Lovato co-starred on “Sonny with a Chance.” ©Disney Channel/Courtesy Everett Collection

Spencer writes that throughout Lovato’s time on the Disney Channel that she “suffered from bulimia, self-harm and substance abuse.” Her mother would find bloody tissues, from Lovato cutting her wrists, throw them out and rush her daughter out the door to make the “Sonny” set on time.

(Lovato’s mom, Dianna De La Garza, wrote in her memoir that she felt powerless to control her daughter, since Lovato was the breadwinner of the family and the star of a show in which hundreds of people relied on her for their jobs.)

“I wasn’t sleeping, and I was so miserable and angry, too, because I felt like I was being overworked, which I was,” Lovato said in a 2020 reunion with the cast for “Sonny.”

Disney continued casting Lovato in original movies and series, sending her on tour and into the recording studio. Once Lovato turned 16 she got her GED and therefore no longer required a guardian on set. Channel reps rarely accompanied her on the road, writes Spencer.

Demi Lovato dated her “Camp Rock 2” co-star Joe Jonas for a time. ©Disney Channel/courtesy Everett / Everett Collection

It all came to a head in 2010, during the South American concert tour for the DCOM “Camp Rock 2,” which Lovato starred in with ex-boyfriend Joe Jonas.

One of the dancers on tour had reported Lovato’s Adderall use to the higher-ups, and Lovato retaliated by punching her in the face, an incident the star recalls in her 2017 documentary “Simply Complicated.”

Within hours, she was dismissed from the tour and sent back to Texas and then to a treatment center outside of Chicago. 

Three weeks after the incident, the channel announced it would begin filming season 3 of “Sonny,” without Lovato.

Raven-Symoné of “That’s So Raven” had two breast reductions and liposuction before her 18th birthday. ©Disney Channel/Courtesy Everett Collection

In 2009, the Disney Channel devised a program for young stars and their families to help navigate the limelight, but for some it was too little, too late.

By the time she turned 18 in 2003, Raven-Symoné had already had two breast reductions and a liposuction. She has said no one at Disney said anything about her weight, but the public, press and her own father did.

In 2011, Gomez was hospitalized for exhaustion.

In the book, Marc Warren, showrunner for “Even Stevens,” tells Spencer of how a 12-year-old Shia LaBeouf had to audition over and over to keep his role on the show.

Shia LaBeouf was made to keep auditioning for “Even Stevens” even after he’d started shooting the show. ©Walt Disney Co./Courtesy Everett Collection

“It’s an exploitative business,” Warren says. “There’s that one-thousandth of a percent of incredibly talented kids who are driven and are born to do it. A kid like Shia, he was doing standup at 10. He was born to it, and it screwed him up. But would he have been screwed up if he wasn’t an actor? Maybe worse. Probably worse.”

At one point, LaBeouf was made to do a callback after he had already started shooting the show. A casting director found him hiding between two filing cabinets, sobbing.

“What do I have to do to prove myself to them?” LaBeouf reportedly said. “I can’t do it again! I can’t!”

The Post has reached out to Disney, Efron, Lovato, Cyrus, De La Garza and LaBeouf for comment.