Sir Roger Moore stated in his memoirs that neither he nor Stacy Keach understood the movie they were making, and still didn't understand it when watching the final print.
The car that Stacy Keach drives at high speed through San Francisco is a 1975 Chevy Monte Carlo.
This was heavily advertised on television for its U.K. and Ireland release, which would have been very unusual in the mid 1970s. It was shown as part of a double bill with No.1 of the Secret Service (1977).
Tony Curtis was first approached to play the part of Ulisse.