John Hamilton Davidson (born December 13, 1941) is an American actor, singer, and game show host known for hosting Time Machine, Hollywood Squares, and That's Incredible! in the 1980s, and a revival of The $100,000 Pyramid in 1991.

Davidson was born to Dr. James Allie Davidson (1908–1984) and Elizabeth Emma Beck (1908–1996), both Baptist ministers, in Pittsburgh, Pennsylvania. He lived in West Bridgewater, Massachusetts, and graduated from White Plains High School in White Plains, New York, and then entered Denison University.^{[citation needed]}

Davidson considered following in his parents' footsteps, but ultimately decided that he "would rather sing about love than preach it."

Davidson worked in situation comedies, game shows, variety shows, and talk shows. In 1964 he appeared in the Hallmark Hall of Fame presentation of The Fantastiks with Ricardo Montalbán and Susan Watson. In the summer of 1966, he was the host of two prime-time variety hour shows, The Kraft Summer Music Hall and The John Davidson Show, the latter of which included George Carlin and Richard Pryor. In the 1980s he became well known for co-hosting That's Incredible! (1980–84), a human-interest/stunt-themed series.

In 1967, Davidson made his film debut in The Happiest Millionaire, alongside Lesley Ann Warren and Fred MacMurray. The following year he appeared with Warren again in The One and Only, Genuine, Original Family Band. He appeared as a guest singer on The Carol Burnett Show in 1967 and 1969, and as the Mystery Guest on What's My Line? in 1969. His career was managed by Alan Bernard, former manager of Andy Williams and one of the partners in BNB, the largest personal management firm in the 1970s.

In 1987, during an appearance on Scrabble he mentioned that he appeared as an underwear model in the 1959 Sears catalog, when he was seventeen. He made his Broadway debut in the 1964 production of Foxy, which starred Bert Lahr. He also appeared in State Fair in 1996.

He was a member of the repertory company on the short-lived CBS variety show The Entertainers (1964–65). He was a regular player on many anthology and variety series of the 1970s–80s, including The Ed Sullivan Show, The Sonny & Cher Comedy Hour, Love American Style, The Love Boat, Fantasy Island, and Spenser: For Hire.

Davidson made numerous appearances on the original Hollywood Squares, from the game show's premiere in 1966 to its cancellation in 1981. He was known for his long-winded bluffs which often fooled contestants with his often ridiculous answers to questions the program's host, Peter Marshall, posed. Most times, Marshall could barely conceal a grin as Davidson began some far-fetched but plausible explanations for his answers, often prefaced with some misleading statement like "I just read about it in the New England Journal of Medicine, it was a fascinating study, and it said that..." Davidson put over these preposterous stories with such sincerity that many a contestant was fooled more than once.