By Laura Herbert
Entertainment reporter, BBC News
A record-breaking 17.2 million viewers tuned in to watch the debut of High School Musical 2 in the US, but will it receive a similar reception in the UK?
The TV movie premieres on the Disney Channel on 21 September following a month-long publicity campaign.
Anticipation for the screening has been built with near-military precision - as music videos, public appearances and internet trailers fuel fans' fervour.
It is a far cry from the slow-burning, word-of-mouth success its predecessor enjoyed.
The original film debuted with little fanfare on the US Disney Channel in January 2006.
Telling the story of two pupils who fall in love as they audition for a school play, it was just one of 10 such movies created for Disney that year, and its phenomenal success took the corporation by surprise.
But since its release 170 million people in 100 countries have seen High School Musical.
The soundtrack, made up of catchy songs like Breaking Free, has sold more than five million copies in the UK and US alone.
Film number two follows the students of East High during their summer break as they try to find work.
Returning lead characters Troy Bolton (Zac Efron) and Gabriella Montez (Vanessa Hudgens) find their relationship put to the test as the summer progresses.
It has been described as a modern-day Grease - although it has none of the sex, drugs and teenage pregnancies of John Travolta's hit film.
"I think we aimed a bit younger," says 19-year-old Efron, the film's heart-throb lead.
"Kids have new values these days. We represent that. This is a new generation of good kids," he added.
Director and choreographer Kenny Ortega describes the Disney Channel as "a safe zone".
Ashley Tisdale plays domineering Sahrpay Evans in the film
"It is a channel dedicated for children's viewership, so we were challenged to make a film for a very specific audience."
But Ortega, who mapped out the dance moves for Patrick Swayze and Jennifer Grey in Dirty Dancing, admits that High School Musical has "gone beyond" its original target audience.
When the sequel premiered in the US in August, it smashed viewing records for a programme broadcast on a cable channel.
Researchers said the audience, which reached 17.2 million, would have been even higher if fans had not held mass "viewing parties" across the country.
Ortega says the unexpected success is "beyond anything that I imagined".
"We didn't go into making High School Musical thinking there was going to be a second," he says.
It is a feeling shared by his young cast.
Stars Efron and Hudgens are also an off-screen couple
Ashley Tisdale, 22, who plays the arrogant, scheming Sharpay Evans, says the phenomenon "blew our expectations".
"If that happens here [in Europe], that's amazing".
In an attempt to make that a reality, the cast spent a week in the UK earlier this month, courting the press ahead of the film's European premiere.
They were mobbed by more than 1,000 eager fans at an event in a London record store, and hundreds more turned out to a red carpet screening of the film at the O2 arena.
"They are so excited to be here, it makes us that much more excited," said Lucas Gabreel, Ryan Evans in the film.
But success has also brought large amounts of media scrutiny, in particular for Hudgens and Efron, who also have an off-screen relationship.
Hudgens says her way of coping with the scrutiny is to "stay positive and don't read anything about myself, then I think I'm better off".
Ortega choreographed Dirty Dancing and Madonna's Material Girl
But fame has also benefited the star - she released a solo album last year and recently won the Teen Choice award for female breakout artist, beating Amy Winehouse, Lilly Allen and Corrine Bailey Rae.
"It was crazy," she says. "I thought Amy Winehouse was winning, I did not expect it at all".
For now, however, her attention is focused on High School Musical.
A third instalment of the million-dollar franchise is in development, with filming due to start in January 2008.
There had been rumours that Efron would not reprise his role after the actor reportedly said he no longer wanted to appear in musicals.
At a press conference in August, he refused to be drawn on the issue, stating: "I can't confirm or deny anything at the moment."
But by the time of High School Musical 2's London premiere, he seemed more certain.
"How could I not come back and do High School Musical? It's the most fun you could have in this business."