NEW YORK — Disney’s smash “Who Framed Roger Rabbit” is finally headed for the sequel route. Sources say Disney is moving ahead trying to get a sequel that would be squarely in the spirit of Busby Berkeley musicals. The score has already been written by Alan Menken, who, sources say, might come aboard as a producer. Menken’s composing credits include “Little Shop of Horrors,” and most of the recent Disney animated films.

Disney has tried for years to mount a sequel to the original, which was made in 1988 at a cost of $55 million. “Rabbit” was responsible for reviving the studio’s animation efforts, grossing $400 million worldwide. The studio first tried to do a direct-to-video sequel. Now, they’re getting more ambitious. Sources say the film will be a prequel, chronicling Roger’s move to Hollywood and efforts to break into the business. Frank Marshall, who with Kathleen Kennedy produced the first, is a possible director.