02/26/2007 at 01:00 AM EST
Sure, the Grammy Awards boasted their share of fashion moments. But none was as dramatic as Britney Spears
's spontaneous style overhaul while out clubbing in New York City on Feb. 11. The pop singer–who drank champagne with friends and debuted songs from her upcoming CD at Tenjune the night before–headed to meatpacking district restaurant-club ONE. Clad in a shiny red minidress, "she was complaining she didn't like it and wanted to change," says a source. Spears called over a couple of the club's go-go dancers, who took her downstairs to their dressing room to try on outfits. Presto-change-o! She partied the rest of the night in a borrowed bikini, busboy jacket and fishnet stockings. "She just hung out with these two dancers all night and kind of befriended them," says the source. A few hours later it was time for yet another change–back into her more demure mommy role as she headed with sons Sean Preston and Jayden James to the airport, where the threesome boarded a private jet bound for L.A.