While filming in Ireland, they ran out of sunshine, so they shot quite a few of the beach scenes at Noordhoek Beach, located a few miles from Cape Town in the Cape Peninsula, South Africa. Those scenes are easy to identify because the sky is particularly bright and clear, and the beach sand exceptionally white and fine.
The movie's long gestation did not endear Sir David Lean to MGM, who soon regretted giving Lean carte blanche after Doctor Zhivago (1965). At one point, MGM President James Aubrey arrived in Ireland to demand that Lean pick up the pace. Lean responded by shutting down production until Aubrey left the country.
Reportedly, many people, including Sarah Miles, felt Trevor Howard, rather than John Mills, should have won Best Actor in a Supporting Role.
As problematic as the production was, Robert Mitchum said that he felt his performance in the movie ranked amongst his best, that Sir David Lean was one of the best directors with whom he had worked, and that he regretted the movie was so poorly received.
Christopher Jones and Sarah Miles did not get along. Not only was Jones in mourning for his close friend (and possibly ex-girlfriend) Sharon Tate, who was murdered by the Manson family during production, but he was also engaged to Olivia Hussey (said engagement was ultimately broken off), and was simply not attracted to Miles. At one point, Miles conspired with Robert Mitchum to drug Jones' breakfast to make him get over his disgust at filming the scene where Rosy and Doryan have a tryst in the forest, but Mitchum overdid the dosage, rendering Jones nearly catatonic for filming of the scene and leading him to believe he was having a nervous breakdown. A combination of grief over Tate's death and his negative experience working on this movie prompted Jones to retire from acting. He only made one other movie. His performance was one of the most criticized aspects of this movie.