Producer David Heyman's relationship with Alfonso Cuarón actually began well before he tapped the filmmaker for a new direction in the "Harry Potter" franchise back in 2004. They were thinking of collaborating on an adaptation of William Sutcliffe's 1999 road trip novel "Are You Experienced?," but the project fell through. Cuarón went on to make "Y Tu Mamá También" and Heyman went on to shepherd the "Harry Potter" books to the screen. When it came time for a stylistic detour in that series, Cuarón was the first artist Heyman had in mind.

"There were several reasons I thought he was the perfect choice [for 'Harry Potter and the Prisoner of Azkaban']," Heyman says. "One, I loved 'A Little Princess' and I also liked his first film a lot. I felt that he had a really keen understanding of teenagers. 'Y Tu Mamá' was about the last moments of being a teenager and this third 'Harry Potter' was about the first moments of being a teenager. He was good at bringing sort of the truthfulness to the relationships."

For Heyman it was about cultivating a sense of modernity to an already wildly successful film franchise. The way to sustain the series was to reinvigorate it after director Chris Columbus had done such a definitive job of setting up the world. "Even though, funny enough, his film was the least successful of the eight financially, Alfonso sort of redirected the series in such a way that it allowed us to continue on to make eight films," Heyman says. "He allowed us to grow up."

Cut to five years later and Cuarón is out on a bit of a limb with a hugely challenging concept: "Gravity." Heyman didn't even need to read the script to know that he was in for whatever ride was in store. And as it would turn out, it would be quite the eventful ride indeed, both in front of and behind the camera.

"I would make the phone book with Alfonso Cuarón," Heyman says. "When he asked me to get involved there was not a moment's hesitation. And when I read the script, I really loved it.  It was an edge-of-your-seat script and I thought it would be great to work with him, but I had no idea how challenging and hard it would be to make because Alfonso's vision was so specific with these long shots and sort of the way he wanted the film to look. You know, three shots take up 30 minutes of the film. At the end of it we had to develop methods with which to realize it."

Cuarón is a filmmaker, Heyman notes, who is "quite rightly" challenging. He is always testing boundaries and that, Heyman says, brings out the best in his collaborators. "He never settles," Heyman says. "He's always pushing. So I knew I had a chance to be part of something special and extraordinary because that's who he is."

Nevertheless, even when Cuarón asked Heyman to come on board, no one really knew how this the film would be realized. For a film that took nearly four years to achieve, only 60 days of it involved actual on-set production with actors Sandra Bullock and George Clooney at London's Shepperton and Pinewood Studios with an excursion in Lake Mead for some outdoor photography. There was a long research and development process and even the day before filming commenced, the technology didn't work. "That was a rather heart-stopping moment," Heyman confides. But it worked out, and here "Gravity" sits, a technical marvel unlike anything the cinema has ever seen.

Such an experience is both thrilling and terrifying, Heyman admits. It's scary in the sense that Cuarón is a filmmaker constantly evolving during production, constantly changing things, bending the process to the shape of his vision. Finding the right path to those ends can be a bit of an adventure. But that, too, is why it's so thrilling.

"It's hard but it's also exciting because you know that every step of the way he's making it better," Heyman says. "And as I said, when you work with him you know you're going to be part of something that's extraordinary. It's great to be with someone who is willing to push the envelope to such a degree that it might not work. It's what a producer wants, you know?"

Heyman makes it a point to mention repeatedly that Cuarón is the kind of filmmaker who knows precisely the film he wants to make as he sets out to make it. Nothing is left for discovery after the fact, as in, Cuarón is not the sort of filmmaker to shoot a lot of material and "find" the film in the editing. More and more filmmakers seem to gravitate toward that approach, and for someone like Heyman, who's early days in the film industry involved working with David Lean as a runner on "A Passage to India" -- a filmmaker who left no room for error, he notes -- it's refreshing to be confronted with such a willful perspective.

"The films that I like are films that have a very distinct point of view," Heyman says. "And those filmmakers become who there are because they have a real sense of what they are, how it's all going to go together…Even with a big franchises when they're in the hands of people who are filmmakers, whether it be Alfonso Cuarón or Chris Nolan or whoever, you can feel that point. It's what gives it a vision.

"There are films that are made in the editing room. That may work for some films and inevitably the editing room is a place where a film is, you know, it's the next stage in the creation of the film. And even on 'Gravity,' which was very carefully structured and defined, pre-visualized, there were changes. Alfonso made changes because he learned as he went what was working best and what wasn't, how to tell the story in the way that he wanted. But the film he thought about at the beginning was the film we saw at the end. So, too, with "Potter.'"

"Gravity" hits theaters in IMAX and 3D tomorrow.