Burt Reynolds only agreed to make this film because he was under the impression that Sergio Leone would be directing. When he found out it was Sergio Corbucci he tried to pull out, but the contracts had already been signed and it was too late.
The first day of shooting, Burt Reynolds reached the location in the Spanish desert in Almeria, dressed as a Native American and wore a red-haired wig. It was raining, so Sergio Corbucci suggested that Reynolds go for a walk around that beautiful scenery. During the walk, Reynolds met a Spanish young boy who asked if he was a Native American. He walked with the boy until a small Spanish town and he was invited for a drink by the boy's family in their house. When Reynolds returned to the set, the film crew was gone, they had left him in the desert, so he had to spend the night with the family in the house where he has been before. Next morning, Reynolds was a bit angry with the crew, that seemed very funny to Corbucci.
Apparently, during the production of this movie, director Sergio Corbucci drove Burt Reynolds deep into Spain's Almerian Desert and then drove off leaving him there to walk back to town.
When director Sergio Corbucci was approached to make this movie, Marlon Brando was touted as the star. By the time production started the lead had been given to Burt Reynolds. Reynolds and Corbucci did not get along at all.