Kristin Cavallari wore a strapless white bikini as she and her fiancé, Jay Cutler, relaxed poolside yesterday in Miami. The engaged couple lounged in the sun together and did a little splashing in the water before Kristin got to work last night. She tried her hand at runway modeling during Mercedes-Benz Fashion Week's 2012 Swim Week. Kristin wore "the world's first glass bikini" in Diesel's show. She had the support of Jay, who sat in the front row, as she hit the catwalk. The piece that she sported yesterday was revealing, just like the bikini Kristin wore for a photo shoot a couple of months ago.