Five-time Grammy Award-winning singer and songwriter Mariah Carey has been tapped to teach a class on how to use the voice and an instrument. The streaming teaching platform MasterClass announced Thursday that Carey will allow its subscribers into her Butterfly Lounge studio to learn firsthand how the voice can be used to write and produce the melodies, lyrics and instrumentation of a song. "I've never let cameras in when I am creating," Carey said in a statement.