Both big fans of film noir, the real stuff that mines the inner darkness of its characters, director Robert Rodriguez and comic book legend Frank Miller (the man who reinvented Batman) are a partnership made in heaven.
Indeed, so determined was Rodriguez to involve Miller as co-director on the film of his Sin City graphic novels, that he resigned his membership of the Directors Guild of America in protest when they declared it against their rules to have multiple directors.
"They argued that I was an established director and he wasn't. So I told them he directed better than most directors in Hollywood," says Rodriguez, who's now no longer eligible for Oscar consideration.
"If you look at his books he was already a great filmmaker, he was just using paper instead of a camera. I thought what he was doing was so much bolder than anything we were doing in cinema and I wanted to prove that visual storytelling is the same whether it's on the page or the screen."
Having brought in a second director, Miller then added a third. For $1. Quentin Tarantino.
"It took him a while to make Kill Bill, which he thought was going to be a very fast shoot, but I told him if he'd shot it on digital it would have been much faster. So I said next time I was shooting something on digital he should come and direct a sequence so he could see what it's like to work with actors in that way and what the technology was about.
"We shot the scene with Clive and Benicio in the rain, on the road in a car. And there was no rain, no road and no car. He got to see how all that stuff went away and he could concentrate on getting a great performance from the actors.
"He said I was right, that if this had been a regular movie we would have spent all day rigging the car, dragging it down the road, ruining the sound with water and then have to hurry to get the performance in."
Other than a shared love of noir and the visual medium, when it came to casting it turned out that Rodriguez and Miller had something else in common: a perverse sense of humour.
That'd be having Elijah Wood play a silent but deadly womaneating cannibal killer.
"I worked with him on The Faculty," explains Rodriguez. "And he has these piercing blue eyes that women love but which I always found quite creepy.
"I told him that one day I would cast him as a psychopath. I showed him the early test footage and he said 'I'd kill to be in that movie!'. I thought 'Kill? Eat? Yeah'."
Rodriguez sent Miller a videotape screen test of Wood, just sitting there saying nothing.
"Frank got so creeped out by it he said 'Hire him'. He really liked the idea of seeing Frodo eat people."