 American Top 40. The hottest hits, the hottest stars. Number 14. Here's the hot new star whose concerts have both fans and critics on their feet. In his live show, he's performing a mix of new songs from his debut album, along with a few hand-picked classics. Everything from the Rolling Stones' Under My Thumb to the Jackson 5's I'll Be There to an old Frank Sinatra hit, Young at Heart. Talk about diversity. And here he is.