Kristin Cavallari is no longer the girl we knew and loved (and hated to love, and loved to hate) on Laguna Beach . She's since gotten married to football star Jay Cutler, had three children written books , and launched a shoe line. But there's one thing about Cavallari that has remained the same: her hair.Sure, we've seen the star flirt with different cuts — the choppy lob is her signature, though she's also experimented with extensions — but Cavallari has always kept her color the same classic, sun-kissed dirty blond it was when she was a high schooler on TV. So imagine our surprise when we saw her at the Carousel of Hope Ball in Beverly Hills, rocking bright platinum. The reason behind her decision, says to Justin Anderson, creative director of dpHUE and the star's colorist, was for it to be completely unexpected."She wanted to have a real winter white moment and go against the trend of going darker in the fall," he says. Cavallari paired the look with a spray tan and soft-pink lips, as you can see below.