Mischa Barton MBARTON081307_06.jpgLast time it was James Taylor, now it's the Tom Petty concert - at Social @ Ross in the Hamptons - that all the celebs turned out for this weekend. Reformed hottie Mischa Barton showed up to chat a bit, and Renee Zellweger, Richard Gere, Ed Burns, Christy Turlington and Christie Brinkley also made an appearance. Probably not much else to do in New York's sweltering heat than to go concert-hopping!