Unlike Justin Bieber's first few singles, "Baby" recognizes that young relationships can result in unhappy endings. "We're just friends? What are you saying?," the 15-year-old heartthrob asks of his young love interest. "My first love broke my heart for the first time, and now I'm like, 'Baby, baby, baby, oh.' " The midtempo number's undeniably contagious chorus should keep Bieber's tween fan base satisfied, and Ludacris' brief cameo adds a welcome urban twist. "She had me going crazy/ Oh, I was starstruck/She woke me up daily/Don't need no Starbucks," the Atlanta rapper quips. The matchup adds a layer of maturity to Bieber's repertoire and should further solidify his growing presence on the charts. Only time will tell whether his "My World" album, due March 2, will do the same.