Boy band Backstreet Boys surprised the New Kids on the Block concert saturday night at New York's Radio City Music Hall .Nick Carter told the screaming and excited crowd that,"You got two for the price of one tonight''.As the audience started to sing 'I want it that way' subsequently the curtain was lifted and revealed the back street boys who gave the finishing of this song.A gracious Littrell said,"I am grateful to back street boys right there",'We have been back street boys fans for a long time'.After performing their song 'shape of my heart' back street boys left the stage.At that time some fan screamed by telling that 'Bring them Back'.