They've been called heartthrobs, teen titans, and America's new sweethearts. They're international superstars whose movies have been seen by an estimated 455 million people worldwide (which translates to a mind-boggling one-fifteenth of the globe). And their undeniable selling power more than 15 million DVDs, 13 million soundtracks, and more than a million concert tickets has turned a duo of made-for-TV movies into a multibillion-dollar brand for Disney. So why can't the cast of High School Musical 3: Senior Year get some decent digs? ''We always aspired to have these big, grand mansion trailers by the end of the franchise,'' jokes star Zac Efron. ''But we actually just ended up with double bangers, which are, like, not even full trailers. Just little half ones!''
Their trailers may have been small someone call their agents but High School Musical (HSM in tweenspeak) is set to get a whole lot bigger on Oct. 24, when basketballer Troy Bolton (Zac Efron), brainiac Gabriella Montez (Vanessa Hudgens), and the rest of the team make the jump from TV to the multiplex. After HSM2's record-breaking premiere on the Disney Channel last year, studio execs decided the series might be ready to play in the box office big leagues. ''Eventually it was a business decision, not an artistic one,'' says producer Bill Borden, who'd tried to pitch both previous HSMs to Disney as features. Series director Kenny Ortega even considered adding another dimension to the movie literally. ''At one point I said, 'HSM3...D,''' says Ortega, who choreographed last winter's 3-D hit Hannah Montana and Miley Cyrus: Best of Both Worlds Concert. ''I didn't get a big reaction.'' But even in 2-D, HSM3 is betting that the series' legions of young and young-at-heart fans will elect it a box office valedictorian. ''The advantage is that we know who the audience is,'' says Disney president of production Oren Aviv. ''They are rabid and they are loyal. But they need to see the goods.''
In the world of HSM, those goods are razzle-dazzle dance numbers, chirpy songs, be-yourself story lines, and maybe most importantly the floppy-haired leading man. While his costars used their High School vacations to pump out medium-hot solo albums, Disney Channel movies, and small roles in indie fare (Lucas Grabeel appears in Gus Van Sant's Nov. 26 film Milk), Efron tested the Hollywood waters with a splashy turn in last year's $119 million-grossing musical hit Hairspray. That success raised questions as to whether Efron would re-enroll for Senior Year. ''He's our main guy,'' says Ortega. ''I wouldn't have wanted to make HSM3 without him.'' Rumors spread that the actor was holding out for more pay, but he insists that wasn't the case. ''I didn't want to do High School Musical 3 just to do it,'' says Efron, who finally came aboard for a cool $3 million. ''I wanted to make sure that they finished off our senior year with a bang.''
It looks like Efron's going to get his wish. The new film promises 10 original songs and set pieces that honor the scrappy HSM spirit while blowing it up to a multiplex scale. Although Ortega says the nearly $30 million budget up from HSM2's $6 million-plus is very much ''Off Broadway'' compared with pricey musicals like 2006's $70 million Dreamgirls, he did get some cool new toys with the extra cash (at least whatever didn't go to Efron's paycheck). Swooping crane shots add drama to a rooftop duet between lovebirds Troy and Gabriella, while an auto-parts junkyard turns into an ersatz jungle gym for the guys-and-cars jam ''The Boys Are Back.'' There are also five costume changes for the scheming Sharpay Evans (Ashley Tisdale) as she tries to lure her brother Ryan (Grabeel) back to the stage with the Great White Way reverie ''I Want It All.'' ''It's not just 'Bop to the Top' of the ladder anymore,'' promises Tisdale, referring to one of HSM1's adorably low-rent numbers.
Plot has never been HSM's strong point: The story usually centers on a quickly resolved lovers' quarrel between Troy and Gabriella followed by a song-and-dance shindig that would make Judy Garland and Mickey Rooney proud. And for all its big-screen bravado, HSM3 is continuing that trend, as the Wildcats traipse through the de rigueur senior-year highlights of prom, the ''big game,'' a spring musical, and graduation. But college acceptances Troy and Gabriella get into different schools threaten to thwart true love, and maybe squeeze in a smidgen of pathos. ''Overall, the tone of the movie is much more grown-up,'' says Efron. ''You're watching the kids from High School Musical turn into adults.''
Of course, that same transformation has been happening off screen as well. Just before HSM2 debuted, photos of Efron and Hudgens cavorting on a Hawaiian beach seemed to confirm rumors of a relationship that had reportedly bloomed on the set of the first HSM. That was just the beginning. Last September, a nude pic of Hudgens hit the Internet, sparking a media firestorm that made some fans wonder if she would be shunned by Disney come threequel time. The actress soon signed on for HSM3, although it's hard to say whether the scandal will hurt her popularity as a wholesome girl-next-door (her latest album, Identified, failed to crack the top 20 after its June 24 release).
Growing pains might explain why the movie's leads have all decided Senior Year will be their last. ''Even as it was beginning, we knew this was the final chapter for us,'' says Efron. Given the cast's long history, it's no surprise that the final day of shooting was a bawl-fest. ''Kenny made this amazing speech at lunch,'' recalls Tisdale. ''We were all just crying, and our makeup artists were crying putting our makeup back on us.''
With its stars moving on, Disney is faced with the prospect of losing its billion-dollar franchise or finding a way to renew it. To that end, HSM3 introduces three new characters: British drama queen Tiara Gold (Jemma McKenzie-Brown), star athlete Jimmie ''The Rocket'' Zara (Matt Prokop), and fellow jock Donny Fox (Justin Martin). No contracts have been signed yet, though Borden says the trio might replace the original stars for a fourth movie that could land back on the Disney Channel. The newbies would have some big shoes to fill, but at least one of them has had some practice. ''I was one of the crazy High School Musical fans,'' says McKenzie-Brown, 14, who was recruited from a performing arts academy in London. ''I knew all the songs and most of the dances as well!''
For the original Wildcats, passing the HSM torch begs the question: Can they survive outside the halls of East High? ''There's no way you could call High School Musical a hindrance,'' says Efron, who will try to shakeup his image this spring in the Big-in-reverse comedy 17 Again. ''However, I definitely think that there's always a time to move on.... You can't stay in high school forever.'' True, but you can bet Disney would be happy to schedule a five-year reunion.