The highly anticipated High School Musical 3: Senior Year, the first big screen outing for the surprise franchise, is already to smash box office records before its even released.The film, which sees all of its cast return to the roles that have made them famous, has already taken £500, 000 in advanced ticket sales eclipsing the record set by Harry Potter and the Goblet of Fire in 2005.High School Musical started life as a movie for the Disney Channel in 2006 going on to become the most successful movie that Disney Channel Original Movie had ever produced.With a teen fan base the film was quickly dubbed the grease of its time and its lead stars Zac Efron and Vanessa Hudgens became household names.A television sequel followed in 2007 and was met with even more success than its predecessor that the third instalment is the first to make it to the big screen.