By Mark Brown
Today it arrived with 20th Century Fox choosing London to launch Avatar, Cameron's sole movie in 12 years – the last being Titanic with its 11 Oscars and record-breaking box office of $1.8bn (£1.1bn).
Cameron said he was just relieved the movie was finally out there. "We can hold our heads high. We got the picture done by the skin of our teeth. It's been a four-and-a-half-year process and it's a relief to let people see it, to quit talking about it, to forget the rumours."
And there have been a lot of rumours. Rumours that the budget was double the stated amount, more like $500m. Rumours that the 3D effects were making people nauseous. Rumours that the film, two hours and 40 minutes long, was a complete car crash.
The Guardian can reveal that the last two are untrue. The film does not make you feel sick and it is not a disaster. All journalists watching the movie in Fox's Soho headquarters had to sign a form agreeing not to publish a review or even express a professional opinion online or in print before Monday.
So by saying Avatar was really much, much better than expected, that it looked amazing and that the story was gripping – if cheesy in many places – the Guardian is in technical breach of the agreement. It is not a breach, however, to report that other journalists leaving the screening were also positive: the terrible film that some had been anticipating had not materialised. It was good.
There is, though, a certain amount of suspension of disbelief needed when watching Avatar. Cynics might sneer at the plot. The film, set in 2154, revolves around a paraplegic marine assigned to a planet where brutish humans are forcing the natives from their homes to mine a precious mineral, unobtanium, which is the only thing that will keep Earth going.
To get it they need to blast away an agreeable species called the Na'vi – 12ft or so blue humanoids with tails and pixie eyes. Sam Worthington as the paraplegic marine pretends to be a Na'vi through avatar technology. At first he's on the nasty human military side but he falls in love, gains a conscience and so on.
Perhaps most surprising was the politics. At one stage the deranged general leading the attack, with echoes of George W Bush, declares: "Our survival relies on pre-emptive action. We will fight terror, with terror." There is more shock and awe in this movie than almost any other.
Cameron agreed there was a connection to recent events but there were also references to Vietnam, and to the 16th- and 17th-century European colonisation of the Americas. "There is this long wonderful history of the human race written in blood going back as far as can be remembered. We have this tendency to just take what we want. And that's how we treat the natural world as well. There's this sense of we're here, we're big, we've got the guns, we've got the technology, therefore we're entitled to every damn thing on this planet. That's not how it works and we're going to find out the hard way if we don't kind of wise up and start seeking a life that's in balance with the natural life on Earth."
The film will open at cinemas next week and gets its world premiere in London tonight with Cameron joined by the actors Sigourney Weaver, Sam Worthington and Zoe Saldano in Leicester Square.
Audiences will be able to watch in normal 2D or in what Cameron called the "turbo-charged" version, 3D. Some industry observers are hoping that audiences will be so blown away by the effects that 3D starts becoming the norm.
If it does well – and there seems little doubt that it will not – then can we expect more? "We'll see," said Cameron. "But yes, I have a story worked out for a second film and a third film."