"For me, it's perfect," he said. "He's grown up. He has his own life. He doesn't care about Dad. He never calls."

"But then we are writing, and I have to call every day. I have to spend hours on Skype with him," lamented Jonás, who would do most of the typing during their all-night sessions before turning it over to his father when the sun came up. (Alfonso previously collaborated with his brother Carlos, who co-wrote "Y Tu Mamá" and wrote and directed "Rudo y Cursi," which Alfonso produced.)

The hope was to get filming in the next three months — the project, though larger than their road trip collaboration, was still imagined at the time as a "small space movie."

"Alfonso said it's going to be simple," Lubezki recalls, "we have only one actor. We build the rocket and then with three guys we can shoot the movie. But that is Alfonso. And of course, $80 million later, five years later and hundreds and hundreds and hundreds of people working on it, we have this movie."

Months turned into years because the technology had to catch up with Alfonso's vision. Not content to work with wires and other tricks that have been used in the past to re-create space, Alfonso and company spent four years developing proprietary technology to mimic weightlessness — a process that Warner Bros. supported, investing in the development of the technology and staying committed to Cuarón's vision, even though it wasn't shown a frame of the film until six months after the director finished shooting.

Thus the film was created through heavy use of computer graphics. The production worked with visual effects company Framestore on a soundstage outside of London. Special built contraptions allowed the actors to be moved around just enough to simulate zero gravity while the lights and cameras did most of the heavy lifting.

An additional challenge came with Alfonso's desire to draw out his shots. Close to 60% of the film is made of just 12 long, seamless takes.

The result is a film that early reviews have lauded for both its visual achievement and its gripping storytelling. Entertainment Weekly is astonished by the film's "hypnotic seamlessness." The Village Voice calls it "remarkable because it's both a spectacle and a platform for the performers."

A learning experience

What has surprised the father-and-son duo is how the experience has changed their personal relationship.

"I've learned a lot of things from him," Jonás said, "but one is that when you sit down to plan a movie, you sit down to plan a movie you would like to see."

Jonás, according to his father, was easily bored and kept pushing his dad to move the action forward faster and let the audience connect to the characters through the action.

"I would try to intellectualize the whole thing," Alfonso said, "and he would say, 'Well, whatever, that's boring.' And that was frustrating at points, but it forced us to shape it another way. I had to entertain my son."

"It was a true collaboration where Jonás was truly Alfonso's equal," said the film's producer, David Heyman, who previously worked on "Harry Potter" and counts the director as godfather to one of his children. "He likes to say he was just another writer, but being Alfonso's son there was that ability to bring a directness and an honesty to their communication that enhanced Alfonso's work."

Blake Edwards co-wrote two of the 1980s "Pink Panther" movies with his son Geoffrey, and Irish director Jim Sheridan collaborated with daughters Naomi and Kirsten on the 2002 Oscar-nominated script "In America." But there are few parent-child writing collaborations in Hollywood today.

Alfonso says that Jonás helped rejuvenate his passion for pure cinema. The director, known for his painterly visual mastery — his single-shot action sequence in "Children of Men" has been particularly lauded — admits that he had been muddled in midcareer.

"He helped me refine it," Alfonso said. "I always had it, but then you start making your films and shaping your career, there is a point where the stuff you learn and the baggage you've accumulated weighs you down. It's good to strip all that away."

Jonás, whom Heyman describes as having a "quiet confidence," is pushing his stripped-down narrative approach forward on his own now, directing the indie feature "Desierto," based on a script he wrote. Set to begin filming in Baja in January, the thriller set on the Mexican border will star Alfonso's star from "Y Tu Mamá También," Gael García Bernal.

Now it's Alfonso who will wait for Jonás to finish before the duo can collaborate again on a project they are in the beginning stages of writing together.

"If Mr. Important Man gets some time," Cuarón senior said with a laugh, "we can work."