Behind Nick Carter and Jordan Knight's Boy-Band Breakout

New Kids on the Block's Jordan Knight and Backstreet Boys' Nick Carter knew each other before their generation-dominating groups teamed up for a joint tour in 2011, but they'd never spent that much time together. "They kept pairing us off in our choreography routines and we got to know each other better," says Carter. "We had a good chemistry. In the eyes of many people, I was like a blonde version of Jordan."

As the tour went on, they began tossing around the idea of touring as a duo, and maybe even cutting an album. It took a little while, but......