THE third installment of Disney’s runaway hit, “High School Musical,” will unfold at a prom.

“High School Musical 3” will return to East High and lead up to a big finale at the school’s prom, according to reports.

The last film, “High School Musical 2,” was set at a ritzy country club in the desert. Unlike “HSM” and “HSM 2,” the new film will not premiere on the Disney Channel. It’s headed for theaters sometime next year. With the entire original cast set to return, production and rehearsals on the movie have begun.