Here’s American Idol ‘Bikini Girl’ Katrina Darrell in a bikini! Surprise, right! The 20-year-old model from California caused quite a stir on American Idol. First she shocked the judges by auditioning in a string bikini. She then got into a fight with the show’s judge Kara DioGuardi, and now her steamy bikini pictures ‘leaked’. Bikini girls sure knows how to play the game; although I find her fellow contestant Casey Carlson way hotter.