When Mariah Carey and Elton John showed up singing in a car with a relatively unknown British comedian, it was clear Carpool Karaoke would solidify host James Corden's place in late night American TV. Beginning his performance career as a child, Corden has catapulted to a worldwide stage spanning from TV to film to theatre. Today on The Treatment, Corden discusses the challenge, albeit by choice, of creating a variety show every single night while reflecting on the magical moments The Late Late Show has produced, like Paul McCartney breaking down the lyrics to "Let It Be".