The Take That star is penning a number of tracks for TV show 'Britannia High', which is being made by ITV.
Casting for the eight-part musical drama series, which is set in a performing arts school, will take place through a "real-life casting process", which will be broadcast on the station before the series starts.
Talented youngsters between the ages of 16 and 18 who can sing, dance and act have been invited to audition for roles on January 12 and 13 at the London Welsh Centre.
As well as performing songs written by Gary, the eight main stars will be performing routines choreographed by 'Strictly Come Dancing' judge Arlene Phillips.
Filming on the series - which boasts the motto "Life is not a rehearsal" - is scheduled to start in June, and will be followed by a stage show.
'High School Musical' was a TV movie originally made for the Disney Channel which has gone on to achieve phenomenal worldwide success.
A third instalment in the series, starring Zac Efron, Vanessa Hudgens and Ashley Tisdale, is expected to start filming later this year.
TAGS: Music Gary Barlow