High School 4 details announced

High School Musical 3 was the first big screen release in the series

Details about the fourth instalment of the successful High School Musical franchise have been revealed.

The Disney Channel said the film would introduce a new cast of characters and feature a love triangle set against a cross-town school rivalry.

Production will begin later this year and the movie will premiere on the Disney Channel in 2010.

High School Musical 3: Senior Year has grossed $250m (£178m) worldwide since its October 2008 cinema release.

As most of the main characters from the third film, including those played by original stars Zac Efron and Vanessa Hudgens, graduated and headed to college, they will not be reappearing.

However it also introduced three new, younger characters, including one played by British teenager Jemma McKenzie-Brown, who is expected to reprise her role.

The series of films and its spin-offs have proved a lucrative global franchise for Disney since the first made-for-TV movie aired in January 2006.

The first two films have since been seen by some 300 million viewers in more than 100 countries, including India, China and Russia.

It has also produced a hit soundtrack album, a concert tour and a vast range of toys, clothes and books.