The Brit, who stars in the movie and is also a producer, teamed up with his fellow actors for the latest edition of his U.S. late night talk show's "Crosswalk the Musical" segment on Thursday (02Sep21).
Corden, who was dressed up as Cinderella's fairy godmother, quipped he had given Billy the wrong address for the spot because he's "intimidated" by the "Pose" star's talent.
"Billy Porter is the only actor I've ever encountered who is almost as talented as I am," he quipped, but of course the Emmy winner soon appeared in shot, immediately joking he's "the only one that's going to be playing the fairy godmother" - as he does in the film.
The funny TV clip wrapped with Billy getting his own back on James, who plays a mouse in Cinderella, by turning him into one of the tiny critters.
"Bibbidi-bobbidi bye b**ch," Porter joked to camera.
The new version of the classic fairy tale premiered on Friday (03Sep21) on U.S. streaming site Amazon Prime.