One night after a hard day's filming, Robert Mitchum and Richard Harris went for a few drinks in Dublin. Late in the evening, a patron in one of Dublin's hostelries recognized Mitchum, and excitedly asked him for his autograph. Mitchum duly obliged and the delighted fan went to show it to his friends. Only then did he realize that Mitchum had signed it "Kirk Douglas". Furious at being made a fool of, the disgruntled fan threw a punch at Mitchum and apparently mayhem ensued. Dublin newspapers were only delighted to report the Hollywood star's barroom brawl.
Robert Mitchum and Richard Harris did not get along very well at the start of filming. But later, when Mitchum got into a bar fight with a group of men, Harris came to his aid and the pair became lifelong friends.
The title "A Terrible Beauty " comes from a line in a W.B. Yeats poem.
The film takes place in Ireland in 1941.