Trouble at East High?!

When the cast of Disney Channel's High School Musical reunited to celebrate the TV movie's 10th anniversary on Jan. 20, there was a noticeable absence.

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Zac Efron, who played lead character Troy Bolton, didn't join the rest of his costars to reminiscence about the film, and a new report claims it's because of onscreen love interest and real-life ex Vanessa Hudgens!

high school musical disney channel
Disney Channel

Part of the cast at the HSM reunion.

“Zac wanted to go to the HSM reunion," a source says of the 28-year-old. But he ultimately didn't go because Vanessa "did not want him there.”

After meeting on the musical's set in 2005, the duo dated for five years before calling it quits. “The last time the two were at an event together she was not comfortable because [her] new boyfriend isn’t cool with Zac,” the source tells OK! magazine.

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Vanessa, 27, has been dating actor Austin Butler since 2011 and Zac has been seeing model Sami Miro over the last year.

Scroll down to see what the rest of the cast is up to these days!