Michelle's caricature was used in the special "Really Loud Music" as a judge of America's Next Hitmaker. This caricature is voiced by Rachel Butera, but her singing voice was portrayed by Lewis.
According to Doug Rockwell, the reason why Michelle did not voice her caricature in the episode outside of her singing voice is because she was unable to convey the appropriate behavior for the character, most namely, the sour/negative attitude when Luna expresses a desire to be herself instead of Lulu.