The Backstreet Boys have been forced to cancel their New York City promotional tour because member Brian Littrell has been diagnosed with the swine flu. The other three members -- Nick Carter, Howie Dorough and AJ McLean -- have seen a doctor and are not showing any symptoms.

"We were really looking forward to spending time with our closest fans and friends in NYC... I hope we can come back soon and do everything we can to help," Littrell said in a statement Monday.