Director Álex de la Iglesia wanted Clint Eastwood to play himself in the film. He even offered to move to Los Angeles to shoot Eastwood's part. Eastwood, who was then working on the production of Mystic River (2003), was forced to turn down the offer.
De la Iglesia thought this was going to be a cheap movie, but in the end it cost a little more than he thought. According to Sancho Gracia, the main character of the film: "I used to say to him 'Álex you're going to ruin' and he said yes, he was going to ruin, but he was going to make the movie that he wanted".
The character of "Julián" (Sancho Gracia) is clearly inspired by a series of real anecdotes from the biography of the actor Aldo Sanbrell, a regular at Spaghetti Western Almería.
It is based on an idea of the director himself and his usual scriptwriter, Jorge Guerricaechevarría, that came up after seeing a show for tourists in Almería, where they were looking for exteriors for the unproduced "Fu Manchú" reboot.
The opening theme music played on guitar samples the famous opening theme from The Good, The Bad and The Ugly. Both films were filmed in Spain and this film is a homage to that one.