Dick Clement later said Kirk Douglas requested a meeting before filming started. "Being an American, Douglas got straight to the point. He said I can't play comedy. And do you know what - he couldn't."
For its French release, Marlene Jobert (Fabienne) was billed above Kirk Douglas (Andrej).
Tom Courtenay (who was not yet Sir Tom Courtenay) had returned to film after a two year absence: In 1969 he starred in the same director's other spy comedy, Otley, and this would be the last theatrical motion picture Courtenay appeared in until The Dresser in 1983. He worked mainly on stage, and a few television movies.
John Thaw (the bearded Albanian man) and Garfield Morgan (the cuckold husband) not only both appear in different scenes parodying the bedroom farce, but, most importantly, both would star in the cop series The Sweeney.
There was a discarded idea for a spectacular ending to the boat chase put forward by the director whereby either the British Gunboat or the East German boat would explode, but the idea never reached fruition, as neither owner would agree to sell their craft.