Frank Sinatra married actress Mia Farrow on July 19, 1966, when she was 21 and he was 50. At the time, Sinatra was enjoying a wave of renewed popularity as the song "Strangers in the Night" returned him to the top of the Billboard charts only seventeen days later. They met on the set of Sinatra's film Von Ryan's Express. She agreed to appear in his 1968 film, The Detective, but when she reneged due to her filming schedule for Rosemary's Baby overrunning, Sinatra served her divorce papers in front of the cast and crew. They were divorced in Mexico in August 1968.

Source: Wikipedia