Backstreet Boys Make the New Kids Fans Scream By Aileen Wong/ Monday June 21, 2010 11:40 AM EDT AJ McLean, Nick Carter and Joey McIntyre Janette Pellegrini/WireImage Boy band fans got a tuneful surprise Saturday night at New York's Radio City Music Hall when the Backstreet Boys made a surprise appearance at the New Kids on the Block concert. "You get two for the price of one tonight," Nick Carter told the screaming crowd. The New Kids on the Block – Joey McIntyre, 37, Donnie Wahlberg, 40, Danny Wood, 41, and brothers Jordan, 40, and Jonathan Knight, 41 – were sitting in front of a white curtain bantering when they launched into the Backstreet Boys's 1999 hit "I Want It That Way," an hour into the concert. As the audience began to sing, the curtain lifted, revealing the Backstreet Boys – Brian Littrell, 35, Nick Carter, 30, A.J. McLean, 32, and Howie Dorough, 36, who finished out th...