Pet Star was a show on Animal Planet hosted by Mario Lopez.The show is a contest between owners and their trained pets who perform tricks. The tricks are graded by three celebrity judges on a scale of one to 10.In the end, the three pets (or more in the case of ties) with the highest score come out as finalists, and the audience votes on who is the episode's Pet Star. Then, at the end of the season, the winners compete to be the year's ULTIMATE PET STAR.