Billy Ray Cyrus becomes Dr. Clint Cassidy Sunday (March 11) when his television series, Doc, premieres on the PAX TV network. Beginning as a two-hour movie at 8 p.m. ET, the show has been picked up for 13 episodes. The "Achy Breaky Heart" singer portrays a country doctor from Montana who moves to New York City. Shooting began in December and continues through April in Toronto.