HSM's Zac Efron has appendix op

High School Musical star Zac Efron has had emergency surgery in America to remove his appendix.

The 20-year-old actor who starred as Troy Bolton in the hit movie, had the operation at a Los Angeles hospital.

Zac was taken to hospital a day after it was confirmed he will be appearing in the third High School Musical film.

High School Musical 3: Senior Year will follow Zac and his co-stars as high-school seniors, putting on a musical before they graduate.

Zac will be joined by Vanessa Hudgens, Ashley Tisdale, Lucas Grabeel, Corbin Bleu and Monique Coleman, when filming starts in the spring.