The most recognizable stars of Baz Luhrmann's cattle-drive drama "Australia" are Nicole Kidman and Hugh Jackman.

But on a December day nearly two years ago, even as Kidman flitted about Luhrmann's creative compound in the hills above Sydney, all of the Australian writer-director's attention was focused on an actor who is just as important a member of the ensemble: a 10-year-old Aboriginal boy who had never acted in anything.

Luhrmann's new movie is as ambitious as its weighty title suggests.

"Australia," which opened Wednesday in Sacramento, represents an unusual amalgam of his heightened, modern theatricality, perhaps best exemplified in his last film, 2001's mashup musical "Moulin Rouge!" and classic old-school historical epics such as "Out of Africa," "Gone With the Wind" and "Lawrence of Arabia," three films Luhrmann often refers to. Blending those seemingly incompatible filmmaking styles – over-the-top outrageous on one hand, formal and restrained on the other – was not Luhrmann's only goal, although it turned into a daunting challenge.

He also wanted to dramatize his native country's less-than-virtuous recent history: One of "Australia's" central conflicts hinges on the government's campaign to separate mixed-race children (half-Aboriginal, half-Caucasian) from their parents, a failed "stolen generation" attempt to make the population more white.

In the film, that half-caste child is named Nullah. It is this young boy who comes between, and ultimately helps bring together, the story's horseback-riding Drover (Jackman) and the English aristocrat Lady Sarah Ashley (Kidman) who has traveled to Australia to discover what has become of her husband and their failing cattle station. If the film was to succeed emotionally, Luhrmann knew on that day in late 2006, Nullah must captivate not only Drover and Lady Ashley, but also the audience.

The director and his casting department had discovered Brandon Walters among nearly 1,000 hopefuls in the tiny western Australia town of Broome, and the young boy had come to Luhrmann's estate, called Iona, with his family for a final meeting.

"It will be a little bit of play, and a little bit of serious work," Luhrmann said to Walters and his family of what he had in store for the boy that day, a schedule that included shooting plastic rockets with Kidman and singing beside Luhrmann's piano.

"But we need to find out if it's a good thing – for all of us to spend the next year together. We still have to say at the end of the week, 'Is this right?'" Luhrmann told them.

As Walters and his family went off, Luhrmann expressed confidence in his choice, but knew how crucial it would be. "Is it right for the movie?" he asked. "Is it right for the story? Is it right for them?" In the end, hiring Walters was among the easiest decisions Luhrmann would face. The production ultimately would go months over schedule, costing Kidman a chance to star in "The Reader," an adaptation of Bernhard Schlink's novel. The production delays – some caused by weather, some the result of Luhrmann's shooting a considerable amount of film – would rekindle the fractious relationship between Luhrmann and 20th Century Fox, which also produced "Moulin Rouge!" (The studio says the film is "great" and that it didn't interfere with Luhrmann's work.)

Well after the film finished principal photography, Luhrmann would be puzzling over his film's final frames and the fate of one of the film's central characters. Even though "Australia" would cost well more than $100 million, the production would have to cut its shooting schedule to save money, and buy and later auction several hundred cattle after feuding with Fox over what kind of cows the movie did or didn't need.

Just days before the film's scheduled release, Luhrmann was still working on the movie. A relentless perfectionist (he and his producing partner-production designer wife Catherine Martin held nearly a dozen meetings finalizing their Christmas card), he was adding a scene here, dropping one there, cutting in new music cues, as Fox fended off countless requests to show a film it didn't yet have.

Fox, which has suffered through a woeful year, very much needs a critical and commercial success. And "Australia" faces strong competition this season from several other high-profile films, including David Fincher's "The Curious Case of Benjamin Button," Danny Boyle's "Slumdog Millionaire" and Sam Mendes' "Revolutionary Road."

"The risk," Luhrmann said, "is staggering."Luhrmann tried to prepare everyone for what lay ahead. Full of energy and willing to share stories about how out of place he sometimes felt among real cowboys, Luhrmann started revving up his troops.

"It's going to be hard, because the ambition of the film is absolutely enormous," he said. "It is every single person's responsibility in this room to directly contribute to making this story as good as it can be. If we can just put a little bit of beauty in the world, it will be worthwhile."

After test audiences gave mixed verdicts, Luhrmann struggled overthe film's conclusion.

"It was just relentless and endless and everything was harsh and hard," Luhrmann said of the production. But the film's hopeful message, is what kept him going, he said, and he's especially pleased that a movie about half-castes is arriving just weeks after the United States elected a mixed-race man its president.

"The film is ultimately about family, but not a nuclear family," the director said.

"And family is defined by those you love and those who love you back.

"That is what it's about – that in these times, we come together, through love."