Kristin Elizabeth Cavallari is an American reality television personality and actress best known for her appearances in the MTV series Laguna Beach: The Real Orange County and its spin-off, The Hills.In May 2009, Cavallari confirmed that she will be joining the cast of the popular MTV reality series The Hills. She appeared in the mid-season finale that aired on May 31, 2009 and will appeared as a regular in the remainder of the fifth season. She has inked a deal with MTV to appear as a series regular throughout two more seasons of the series following the fifth.