Britney Spears' estranged husband KEVIN FEDERLINE shocked audience members at Justin Timberlake's Las Vegas gig on Friday night (19JAN07) when he showed up at the concert. On Thursday (18JAN07), just days after Spears left Las Vegas after spending a lavish weekend with model ISAAC COHEN, her two exes arrived in town separately. Timberlake was in Sin City to perform at the MGM Grand, while Federline was in town to check out the World Extreme Cagefighting matches at the Hard Rock Hotel. They both were spotted at Tao nightclub on Thursday (17JAN07), where Federline spent most of his time in the VIP section at a table next to some of Timberlake's dinner companions. According to one club-goer, "He wasn't drinking much and really only talked to a couple of his friends. It seems like he's trying to move on from past Vegas visits where it was all about the bling bling." Their paths crossed the following night (20JAN07), when Federline, along with Alyssa Milano, David Hasselhoff, Toni Braxton and Taye Diggs, caught Timberlake's show.