"We've got a script, we're developing the music, and it looks like we've rounded up the cast. We're looking at dates," Ortega told the New York paper.
Pre-production on the third installment — which will be a feature film to be released theatrically — is expected to start in January 2008. Filming will take place in Salt Lake City, Utah.
"I can say, we're sort of returning to East High in the last year of the Wildcats," Ortega divulged about the plot.
Ortega ("Newsies"), who both directed and choreographed the original film and the first sequel for the Disney Channel, will return for the third movie to be penned again by writer Peter Barsocchini.
The original stars include Zac Efron (as Troy), Vanessa Hudgens (Gabriella), Ashley Tisdale (Sharpay), Lucas Grabeel (Ryan), Corbin Bleu (Chad) and Monique Coleman (Taylor). Disney's original "High School Musical" has already spawned sing-along, dance along and pop-up editions, two soundtracks, two DVD versions, games, two stage versions, a concert tour and an ice show. "High School Musical 2" will be released on DVD Dec. 11.
Visit the "High School Musical 2" website at disneychannel.com/highschoolmusical2 for more information.