First Paris, and now sister Nicky Hilton is dating one of Mary-Kate Olsen's ex-boyfriends.

Nicky Hilton is rumoured to be dating Mary-Kate Olsen's ex-boyfriend - just days after sister Paris was linked to another of the pretty twin's former lovers. The sexy socialite was spotted out with David Katzenberg, who dated Mary-Kate for nine months last year, at her 22nd birthday party in West Hollywood. . . . . .Full Story