The famous sex scene between Donald Sutherland and Julie Christie was a last minute on-set idea from director Nicolas Roeg who felt that otherwise the film would have too many scenes of the couple arguing. Most of the scenes around it are improvised.
Donald Sutherland and Julie Christie met for the first time on the set of this film. The first scene they had to shoot was the sex scene, as Roeg wanted to "get it out of the way" and then move on to the "bone" of the matter. Christie was terrified.
In order to avoid an X-certificate rating for the film's American release, 9 frames (less than half a second) had to be cut from the intimate love sequence between Donald Sutherland and Julie Christie.
In 2011, both co-star Donald Sutherland and producer Peter Katz issued denials to the longstanding rumor that Sutherland and Julie Christie had engaged in unsimulated intercourse during their characters' sex scene.