IT is a little after 7 p.m., and Liam Scarlett, a Royal Ballet corps dancer and the new choreographic wonder boy of British ballet, clad in black jeans and a T-shirt, is courteously escorting a visitor through the backstage corridors of the Royal Opera House here. As the sounds of the orchestra warming up for the evening performance of “The Sleeping Beauty” play through the loudspeakers, Mr. Scarlett casually mentions he’s in the show.

Which role? One of Carabosse’s rats in the Prologue, he says, seemingly unconcerned that he’s due to commence his evil duties, in costume, in 10 minutes. “It’s not a problem,” he says. “I just have to throw on the rat’s head.”

Mr. Scarlett is good at changing hats. On Jan. 6 his new work for Miami City Ballet, “Viscera,” opens at the Adrienne Arsht Center for the Performing Arts in Miami. And while “Asphodel Meadows,” his breakthrough piece for the Royal Ballet, was being performed in November, he was busy choreographing for the maverick troupe the Ballet Boyz, as well as coping with his usual dancer’s schedule of rehearsal and performance...