Before this, Martin played Young Simba in "The Lion King," Prokop appeared in "Hannah Montana" and "The Office" and McKenzie-Brown acted on TV in Britain.
The third High School Musical is due out in October.
Newcomer teens join 'High School Musical' cast
LOS ANGELES, CA Jemma McKenzie-Brown, Matt Prokop and Justin Martin
will play sophomores in the sequel that will focus on Troy,
Gabriella and the others in their senior year. The three beat out
more than 1,000 other actors to land the roles.
