"High School Musical" veteran Alyson Reed will help anchor the spinoff tentatively titled "Madison High," the Disney Channel said on Thursday.
The pilot will feature theater students led by teacher Mrs. Darbus (Reed), who will slide over from the original films to the new Disney Channel pilot.
Newcomer Luke Benward, 15, will play the lead character, Devin Daniels, a motocross racer in need of a new hobby. The Nashville-born actor has previously appeared in the Disney movie "Minutemen."
Also coming aboard is 14-year-old actress Leah Lewis (left), who will play formerly home-schooled tennis champ Peyton Hall.
Filling out the confirmed cast so far is 12-year-old G (yep, just G) Hannelius, who'll play precocious starlet-in-the-making Wednesday Malone.
Disney will begin casting soon for three other characters.
As reported previously, the series went into development in November. The show will be co-executive produced by Lester Lewis, also a producer on "The Office."
The movie "Sharpay's Fabulous Adventure," in which "HSM"'s Ashley Tisdale reprises her role as Sharpay Evans, is scheduled for an April release on DVD.
The original "High School Musical" movies launched the careers of Zac Efron and Vanessa Hudgens. The franchise has been a reliable performer for Disney, with 2008's "High School Musical 3: Senior Year," grossing more than $250 million at the box office worldwide.