James Cameron with his stars on set (Photo: Everett)

Twenty years after he scored what, at the time, was the biggest hit in movie history with 1997's Titanic, director James Cameron for the first time reveals some of the behind-the-scenes drama behind his classic film in this letter he wrote to THR's Stephen Galloway for his new biography, Leading Lady: Sherry Lansing and the Making of a Hollywood Groundbreaker (Crown Archetype, out April 25). Here's Cameron in his own words:

Peter Chernin at Fox [then-20th Century Fox chairman] had made it clear that he wanted a partner to share the pain on a $100 million (or so we thought at the time) chick flick. I told Peter that finding a partner was his problem, I had a movie to make, so I just proceeded hell-bent toward production, and Fox continued to fund the film while they scrambled to find a partner.

In late July of '96, only a couple weeks before we were to start principal photography, and with the construction of the studio in Baja in full swing and the full-size ship set already being built, Casey Silver at Universal passed after a long dalliance. But Paramount was interested — Sherry [Lansing] had read the script and thought it was good. I was due to start photography of the present-day scenes in Halifax, Nova Scotia, in a few days, and had no time to deal with studio politics.

I had one brief call with Sherry in which she was very positive about the power of the script.

I have no idea how much Sherry had to do with all this business maneuvering. She was always the creative interface between us and Paramount, and remained highly supportive of the film.

Sherry was very complimentary about the dailies as we went along. She shared with me later that she was very excited that the raw footage captured the sweep and emotion promised by the script. I had only ever done sci-fi, horror and action previously, so this must have been a relief. However, at the same time the costs were spiraling out of control, so I remember the praise from all parties becoming more sparing as time went on — they didn't want to encourage me to sacrifice schedule for quality.

Read more: The Rollercoaster Drama Behind 'Titanic': An Out-of-Control Budget, Two Warring Studios and a Near-Fistfight

Sherry always loved the film but [when the release date loomed] 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. Everyone thought they were going to lose money, and all efforts were simply to make sure the hemorrhage was not fatal. Nobody was playing for the upside, myself included, because nobody could have imagined what was about to happen next.

In post in the late spring of '97, as we were trying desperately to complete the visual effects in time for a summer release it became increasingly clear to me that we were going to miss the July release date, and we were going to have to make major cuts and compromises in order to meet any deadline in summer. We'd had an extremely successful preview in Minneapolis that gave us our first hint that the movie transcended expectations. But the reality of getting the film done at the necessary level of visual quality was becoming almost impossible. The film was simply too long and the visual effects too unprecedented. It seemed we would miss any date in July and have to push into August, which was considered a dumping ground. And even then, there would be serious compromises to the editing, the effects and the music. Making the film shorter was taking longer. In the cutting room, the film was getting shorter by a few seconds a day — it was liking cutting a diamond. We didn't want to screw it up by hacking at it, but we were desperate to get it shorter.

We were also being pummeled relentlessly in the press, especially the industry trade papers — about epic cost overruns, set safety, delivery dates and just about everything. 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 theaters.

I pitched the concept that the best way to deal with the negative press was to take a step back. To move away from the crescendo of ridicule and let them fall on their face. They could only sustain the negative story so long. By December it would have long ago run its course, and they'd have to come up with something new to make ink. That something might just be the fact that the film was actually good, and worth all the drama of production.