The behind-the-scenes drama that threatened to ruin Titanic

Leonardo DiCaprio and Kate Winslett in the movie Titanic. Photo / Supplied

Twenty years after James Cameron scored the biggest hit in movie history (at the time) with Titanic, he has finally opened up about the behind-the-scenes drama that threatened to sink the project.

In an excerpt from Stephen Galloway's new biography Leading Lady: Sherry Lansing and the Making of A Hollywood Groundbreaker (published in The Hollywood Reporter), the legendary director revealed that the studio totally lost confidence in the blockbuster as it neared its 1997 release date.

"The business heads at Paramount acted like they'd been diagnosed with terminal cancer - a lot of grim faces and a triage approach to releasing the movie," he explained.

"Everyone thought they were going to lose money, and all efforts were simply to make sure the haemorrhage was not fatal."

Plagued by issues with the complex visual effects, and determined to shave the movie's length down to a more manageable size, the director was forced to push back the release date by a month to August - which was considered "a dumping ground."

It didn't help that the movie was being "pummelled relentlessly in the press" - about everything from epic cost overruns to set safety and delivery dates.

"We were the biggest morons in Hollywood history and the press had the long knives out, sharpening them as we approached our summer release. It would have reached a crescendo of scorn just as we put the film in theatres," Cameron said.

He explained that he pitched the concept that the best way to deal with the press was to take a step back - to "move away from the crescendo of ridicule and let them fall on their face."

And it worked perfectly.

"No one more surprised than myself, because nothing like it had ever been tried. But it was a strategy that revealed itself in the heat of battle - necessity was the mother of invention. And desperate times called for desperate measures."

Amid all the drama, studio head Sherry Lansing finally provided a turning point for the movie when she saw the uncut version - and loved it.

Despite his relief at having the drama-plagued production validated, Cameron admitted he still believed it would end his career.

"Nobody thought we were EVER going to break even. And I pretty much assumed at that time that I'd never work again."

As we all now know, he couldn't have been more wrong.

Titanic went on to make $US2.18 billion at the box office, making it one of the highest grossing stories of all time - and cementing Cameron's position as a Hollywood legend.