Dear John was also the name of a song co-written and performed by Elton John.
Dear John was also the name adopted internationally for a song actually called "Dear John Letter" which was very popular worldwide in the 1950s and later. Written by Lewis Talley, Fuzzy Owen and Billy Barton, it was a hit for Ferliin Husky and Jean Shephard, and was later recorded by numerous singers, including Pat Boone in 1960, and Skeeter Davis and Bobby Bare in 1965. It told the story of a woman writing to her boyfriend overseas, explaining that she was breaking off the relationship to marry his brother.
The British sitcom's title was also a reference to letters sent by girls to their absent boyfriends breaking off the relationship. In the opening episode of the series, John discovered that his wife was leaving him for a friend, and was forced to find lodgings. In desperation, he began attending meetings of a singles club, and found the other assorted members mostly social misfits. They included frigid Kate (Belinda Lang), nerdish Ralph (Peter Denyer), outrageous Kirk (Peter Blake) and Louise, the leader of the group (Rachel Bell)
The British production was brought to a premature end by the illness and eventual death from cancer of its star, Ralph Bates, who played John. It was later re-made for the American market with the same title but was called Dear John USA in the UK.