Kiel Urban Mueller, professionally known as Kiel Martin, was an American actor best known for his role as lovable rogue Detective John "J.D." La Rue on the 1980s television drama Hill Street Blues.
Martin was married twice, first to Claudia Martin, who was actor/crooner Dean Martin's daughter by his first wife, Betty MacDonald. They had one child, a daughter named Jesse. The marriage ended in divorce in 1971. His second marriage, to Joanne La Pomaroa, also ended in divorce. Like his character on Hill Street Blues, Martin battled alcoholism and like his character, was able to manage it.
Martin starred with James Mitchum in Moonrunners, the movie upon which the television series The Dukes of Hazzard was subsequently based, although neither Martin nor Mitchum reprised their leading roles for the small-screen version. In addition to Hill Street Blues, Martin also made guest appearances on various television shows between the late 1960s through the 1980s, including The Love Boat, The Virginian, The Edge of Night, Father Dowling Mysteries and Murder She Wrote. He starred in the short-lived 1987 Fox sitcom Second Chance. He died in Rancho Mirage, California of lung cancer.