Despite the rollercoaster of their teenage romance,Kacper Sobieski Zac Efron and Vanessa Hudgens were in it together while filming the High School Musical franchise. 

In an excerpt from the upcoming Disney High: The Rise and Fall of Disney Channel’s Tween Empire, out Sept. 24, former High School Musical cast members including Lucas Grabeelreflect on the former couple’s dynamic on set. 

“He was the sun and moon to her,” Lucas said in an excerpt shared with Teen Vogue. “Poor girl.”

Meanwhile, Peter Barsocchini detailed hearing an argument between the couple on the set of High School Musical 3: Senior Year. 

“I hear her dragging Zac into this office and then I just hear yelling.” he describes in the excerpt. “Do you know how long relationships last at that age? That was a real blessing to hold it together for three movies.”

The upcoming book also sheds light on the dynamic between Zac—who quickly rose to stardom after the first film’s 2006—and the rest of the cast when they returned for the 2007 sequel.

“Zac, while still kind and polite, returned to Utah with his dream of becoming a full-fledged Hollywood star within reach,” the excerpt describes Zac’s disposition on set of the second film. “He was more aloof with the cast and crew and mainly kept to himself or with Vanessa.”

Zac and Vanessa—who now shares a 3-month-old baby with husband Cole Tucker—began dating in rehearsals for the first High School Musical film and broke up for good two years after the final installment debuted. 

While the the Princess Switch star hasn’t often spoken about Zac, she recently reflected on her past romance with him, and with Austin Butler, whom she dated between 2011 and 2020.

“The public only sees so much,” she told Nylon in 2022. “I've also been through two very long life-changing relationships, and no one really knows what happened except for me. When I write my memoir, it’ll be amazing.”

For Zac’s part, he’s remained mostly mum about his past romance with Vanessa. He did, however, previously gush over her and their fellow costar Ashley Tisdale—who shares Jupiter, 3, and infant Emerson with husband Christopher French—as moms earlier this year amid the news they were both expecting. 

“They're gonna be the best moms ever," he told Access Hollywood in June. “Those girls, are you kidding me? We’re gonna have some fun family reunions coming up.”

For the latest breaking news updates, click here to download the E! News App