The Tonight Show is an American late-night talk show currently broadcast from the NBC Studios in Rockefeller Center in New York City, the show's original location (a tradition interrupted by decades of originating from various studios in the Los Angeles region), and it has aired on NBC since 1954. The show has been hosted by six comedians: Steve Allen, Jack Paar, Johnny Carson, Jay Leno, Conan O'Brien, and Jimmy Fallon. It has had several recurring guest hosts including Ernie Kovacs during the Steve Allen era and Joey Bishop, David Letterman, Joan Rivers, George Lucas, David Brenner, and Leno during Johnny Carson's stewardship (along with dozens of occasional substitutes), although the practice has been abandoned since Carson's departure, with hosts preferring reruns to showcasing potential rivals. "The Tonight Show" is the world's longest-running talk show and the longest-running, regularly scheduled entertainment program in the United States. It is the third-longest-running show on NBC, after the news-and-talk shows "Today" and "Meet the Press".