To celebrate the release of her killer throwback debut of '60s girl-group pop, Welsh singer Duffy performed a short-but-sweet set at New York's fabled Apollo Theatre last night. The twenty-three-year-old, pint-sized blonde proved she was the real deal, showing off a voice that sounds like a soul diva three times her age. Bonus: She's totally not as crazy as Winehouse. "The chances of a girl from Wales making it to this stage are pretty slim," she told the crowd, before launching into her swinging hit "Mercy." Click above for more on Duffy from her visit to the Rolling Stone office, including her early influences and the secrets behind her new album Rockferry.