Michael Bublé is making the rounds in New York City this week, promoting his new album "To Be Loved." But in addition to standard TV appearances, he surprised Subway riders Thursday when he performed an impromptu acappella rendition of his latest single, "Who's Lovin' You." Dressed sharply in a suit and tie, Buble sang with the group Naturally 7 at the W. 67th Street subway stop. CLICK ABOVE LINK FOR THE VIDEO