The real star of 'Australia' is the Kimberley Mountains

On a bright October morning, I bumped along the graded Gibb highway toward El Questro, a million-acre ranch in the back end of Aussie nowhere. Iron-red cliffs competed for attention with 1,000-year-old boab trees, distant relations to Madagascar's celebrated baobabs. Their swollen, water-storing trunks underlined the all-embracing dryness, as the 4x4's air con struggled with a thermometer hovering around 42C. And it wasn't even 10am.

To know that this lost outpost in the Kimberley Mountains is a principal location for Australia, Baz Luhrmann's £77m tribute to his homeland, is to understand the film he planned to make. His screenplay was the dry-land version of African Queen, touched with Lady Chatterley's Lover and liberally sprinkled with stardust.

For Katharine Hepburn and Humphrey Bogart, read Nicole Kidman and Hugh Jackman, chilly English aristo and cynical rough trade. When they're cast adrift in the Darwin area in the Second World War, Kidman's on a mission to catch her husband cheating on her and also to sell her derelict ranch, and Jackman's mourning the death of his Aboriginal wife. There would be no story if it wasn't class hatred at first sight.

Luhrmann's parents owned a petrol station, a farm and a cinema in remote New South Wales. But for his romantic epic he wanted an even emptier land to symbolise his country's last frontier. A million acres is larger than Monaco, larger than San Francisco, New York City, Los Angeles, Dallas, Miami, Seattle and Denver combined. And it is quality Gaba (Great Aussie Bugger All), a tangle of barely inhabitable gorges and salt flats, hot springs and water holes in the heart of the Cockburn Range.

In winter, its saving grace is the Chamberlain River that winds through it, a deep home for crocodiles and barramundi. In summer, when its tributaries fill up – creating raging torrents and taking out the highway – El Questro is accessible only by helicopter. It's hard to imagine this on the 70-mile drive from Kununurra airport, but when I draw up outside the Homestead, at lunchtime, I'm transported into a green oasis with a lawn and a swimming pool overlooking the river.

The Homestead is doubling up from six rooms to 12, but preplanning is essential if you want luxury in this wilderness. No vulgar checking in: I sat down under ceiling fans beside my fellow guests, a South African diamond magnate, a Hong Kong banker and a Sydney lawyer, and sipped Perrier Jouët as if we were all chez nous. In the evening, tables were set up on rocky ledges above the gorge. While we feasted under a full moon, we peered down at a crocodile cruising speculatively far below.

The next morning the chopper airlifted me to our heli-fishing base further down the Chamberlain. As an inexperienced fisherwoman, I was surprised to find myself posing with a 3ft, 33lb barramundi within minutes of putting my lure in the water. When the photography was done, my intrepid croc-wrestling guide, David Charles Chilcott IV – Chilli to his friends – lowered my barra gently off the boat and tried to coax the flow through her gills. Luckily she rediscovered the will to swim and off she went.

After breakfast, I tore myself away from the Homestead to check out the rest of El Questro. The impoverished cattle ranch was bought in 1991 by 23-year-old Will Burrell for a million Aussie dollars. He ran it in good ole boy mode, hosting lavish outback parties for his mates. When he was reported for heli-waterskiing down the Chamberlain Gorge in 2004, he realised that PC had taken over his world and sold out, but not before he'd set the ranch up as a wilderness destination.

He organised accommodation to suit all pockets, converting the Homestead and building a family-friendly complex with a restaurant, bar and swimming pool at Emma Gorge, a 40-minute drive away. The Station Township, which has air-conditioned cabins and tents for hire, plus campsite, steakhouse and pub, is the departure point for a hectic schedule that includes riding at dawn and champagne on a bluff at dusk, with scenic flights, Chamberlain Gorge cruises and 4x4 tours of the Cockburns in between.

Nowadays, ranching and tourism co-exist, though guests catch only an occasional glimpse of 6,000 cattle grazing sparse yellow grass. Once Luhrmann had selected the El Questro mud flats as the location for a dramatic stampede, his casting director picked out 1,000 shorthorns to star in the film. "Baz came on a recce three years ago," said David Henry, El Questro's general manager. He hadn't finished the script when he decided to use the Cockburns for the pivotal cattle drive caused by the Japanese bombing of Darwin. During filming, key animal players, both cattle and horses, were stars as of right, with individual personalities and their own doubles.

Kidman, too, had a double for the more energetic stunts, especially fortunate because she conceived during filming. The 41-year-old actress credited Kununurra's water for the birth of Sunday Rose on 7 July 2008. Six other cast and crew members also got pregnant after swimming with her in local water holes. Likewise, Australia ended happily. The hero was meant to die but a Hollywood royal command ensured his joyous survival. Stardust indeed.

Compact facts

How to get there

Austravel (0844 412 4620; austravel.com ) offers a six-night tour of Australia from £2,485 per person, based on two sharing, including flights, two nights at Emma Gorge, two nights' full board at the Homestead and two nights at the Mantra in Darwin. The lodges are open from April to November.

Further information

'Australia' opens in the UK on Boxing Day.