The Hills is an MTV television series that premiered on May 31, 2006. The show uses a reality television format, following the personal lives of several young adults living in Los Angeles, California. The series originally followed the personal life of former Laguna Beach star Lauren Conrad and her friends' new lives in Los Angeles. After five seasons, Conrad chose to leave the series, and was replaced by another former Laguna Beach star, Kristin Cavallari, beginning in the second half of season five. Cavallari signed on for two additional seasons following the fifth.