HOLLYWOOD, Calif. — Backstreet Boys member Brian Littrell has been diagnosed with the swine flu, the band revealed Monday on their Web site.

Fellow members Nick Carter, Howie Dorough and AJ McLean have all been seen by a doctor as a precaution but are not showing any signs of symptoms, the band said. As a preventive measure, the doctor has prescribed Tamiflu to the group and their touring party, who had just returned to the states from Tokyo.

The swine flu news forced the group to cancel their planned appearance at Monday's PINKTOBER event at New York's Hard Rock Cafe.  The band also canceled a performance on tomorrow's CBS "Early Show," where they expected to perform their new single "Straight Through My Heart."

"We were really looking forward to spending time with our closest fans and friends in NYC and take part of PINKTOBER, an unbelievable and important program" the 34-year-old Littrell said. "I hope we can come back soon and do everything we can to help."

The band's seventh studio album, "This Is Us," goes on sale Tuesday.