Zac EfronWe're on the set with the most popular seniors ever -- the 'High School Musical 3' cuties

OMG! Can you believe it?

The popular crowd of East High is set to graduate, in 'High School Musical 3: Senior Year.' But at least the kids, including Zac Efron and Vanessa Hudgens, are going out with a bang by taking their song-and-dance act to the big screen.

Here are a sweet 16 things you must know before you go. You're on your own for earplugs to protect your hearing from the shrill screams of the tween girls.

High School Musical 3' Set Visit

    OMG! Can you believe it? The popular crowd of East High is set to graduate, in 'High School Musical 3: Senior Year.' But at least the kids, including Zac Efron and Vanessa Hudgens, are going out with a bang by taking their song-and-dance act to the big screen. Here are a sweet 16 things you must know before you go. You're on your own for earplugs to protect your hearing from the shrill screams of the tween girls.

    Walt Disney Pictures

    1. Chad and Troy get deeper
    Yes, the bromance continues. "The first two movies, you knew that Chad and Troy were best friends since kindergarten, but you don't really see a lot of emotional contact between the two. But in this movie, you really see it," says Corbin Bleu, who plays Chad. "Out of any of the characters, I think Chad is closest to, and most in love with, Troy."
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    2. The cast was nostalgic before filming even ended ...
    "What will I miss the most?" asks Efron. "I think it's just waking up every day knowing you're going to be with your friends all day. It's just a creative environment. Every day you're challenged, and it's fun, and you're growing ... and I'm rambling." Is that a touch of senior burnout, Zac?
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    3. ... But only one was super weepy
    "The most emotional is always Monique [Coleman]," says Bleu. "Always, always, always. Monique is the crier, and she sets the rest of us off. It's not like she's sappy at all. Monique just has the biggest heart." Or over-active tear ducts.
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    4. The guys have a junkyard dance-off
    "We have our first real duet together," says Bleu. "This was the first time Zac and I really got to dance with one another. It was awesome. The number itself is like nothing anyone's seen before. We're dancing on top of cars in this junkyard, dirt flying everywhere. It's this real macho number." "It was extremely physical," adds Efron.
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    5. Zac was marked tardy for rehearsals
    "I showed up to rehearsals a few weeks late because I was working on a different project," Efron explains. "It was the worst mistake of my life, because I was just kind of thrown into a number of dances that were extremely difficult. I was a little bit intimidated. But after a few weeks, we got it down."
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    6. Troy picks his favorite
    "In this movie, Troy is thinking of completely abandoning basketball and making theater his career," says Bleu. "Chad's whole plan was that they would go to college together and join the NBA. And his plan is crushed right in front of him."
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    7. There's a green theme
    "We've always had this shtick where Chad has sayings on his shirts," says Bleu. "Chad becomes a bit of an environmentalist in this movie, so this time around it was all green sayings." Nike contributed their new green line to the project as well. "I kind of get to launch the movie with it."
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    8. There are new kids on the block
    With the seniors heading for graduation, it's no big surprise that Disney lays the groundwork for 'HSM 4' with a batch of new sophomores: British actress Jemma McKenzie-Brown (as Tiara Gold), Justin Martin (Donnie Dion) and Matt Prokop (Jimmie "The Rocket" Zara).
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    9. The sophomores may seem a little familiar
    Jimmie is a younger Troy (Efron). "He idolizes him," says Prokop. "He wants to be just like him, if not better than him. And he really wants to take his spot on the basketball team." Donnie is a Chad fan. "He looks up to Chad, and he keeps Jimmie from falling off the edge of the earth," Martin says. And Tiara is following in Sharpay's (Ashley Tisdale) footsteps -- literally. "Tiara is a transfer student and she's Sharpay's personal assistant," says the British-born McKenzie-Brown. "So, she runs around after her and sorts her out and stuff."
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