Courtney Love will be paying tribute to a favorite actress of hers, silent film star Clara Bow. Love will narrate the upcoming Turner Classic Movies documentary “Clara Bow: Discovering The It Girl.” Bow was as vivacious as they came, then faded away after mental problems overtook her. (She was married to Rex Bell, an athlete-turned-actor who ended up lieutenant governor of Nevada.) Meanwhile, on rival old-movie cable network American Movie Classics, Billy Bob Thornton, Dennis Quaid and Lauren Bacall are joining the host line-up. Quaid will do “John Wayne Wednesdays”; Bacall, the “Hollywood Fashion Collection”; and Billy Bob, Saturdays’ “Film Preservation Classics.”