DiCaprio led the 1997 box office hit as Jack, who develops a romance with star-crossed lover Rose (Kate Winslet) aboard the doomed Titanic.
Speaking to People at the Golden Globes on Tuesday (10 January), the award-winning director recalled having to “twist” the then 21-year-old actor’s arm to be his “leading man”.
“He didn't want to do a leading man," Cameron revealed. "I had to really twist his arm to be in the movie. He didn't want to do it. He thought it was boring."
Cameron added that DiCaprio eventually “accepted the part” of stowaway Jack only after the Canadian filmmaker “convinced him” that the role was “actually a difficult challenge”.
“It didn’t surprise me, first of all, that he’s made a lot of authentic choices going forward. And secondly, I never doubted his talent,” Cameron said.
In an earlier interview, the director remembered an awkward encounter with DiCaprio during the audition process that almost cost the actor the role.
Cameron shared that DiCaprio “charmed everyone” in the room, but said that the actor told him “I don’t read” upon realising he would be required to audition for the part.
The Avatar director recounted telling DiCaprio: “Oh, yeah. Come on. This is a giant movie that is going to take two years of my life, and you’ll be gone doing five other things while I’m doing post-production. So, I’m not going to f*** it up by making the wrong decision in casting. So, you’re going to read, or you’re not going to get the part.’”
Following its theatrical release, Titanic became the highest-grossing film at the time, earning a whopping $600m (£490m) at the US box office and $1.8bn (£1.4bn) worldwide.
The epic romance drama went on to win 11 Academy Awards, with Winslet landing a nomination for Best Actress.
Beginning on 10 February, a digitally remastered version will return to cinemas in celebration of its 25th anniversary.
In tandem with its traditional Valentine’s Day re-release, an additional special, showing Cameron’s recent “forensic analysis” done to put to “rest” the decades-long Titanic debate, will be shown on National Geographic.