titanic Is 20: Leonardo DiCaprio Worried Plus Filming Movie's Ending Had Cast Laughing 

Why Leonardo DiCaprio Worried His Titanic Role Would Be "Too Easy" and Filming the Ending Had the Cast Cracking Up

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It\'s been 20 years since James Cameron\'s

sailed into theaters and box office history, but one thing is clear: We never let go of Jack and Rose\'s tragic love story.

Leonardo DiCaprio and Kate Winslet\'s iconic characters and their heartbreaking, infinitely quotable romance may be entirely fictional. But the chemistry between the actors was very real—and it was obvious to

"There was a point very, very early where we all realized it had to be Kate and Leo," Rae Sanchini, the film\'s executive producer, tells E! News exclusively.

Winslet "had been very clear from the start she wanted to do it," says Sanchini. But getting DiCaprio on board took some serious convincing from Sanchini and writer-director Cameron.

"I think the hardest thing with Leo was convincing him that there was complexity in Jack Dawson," Sanchini says. "Because when you think about it, Jack is the purest of heart. We meet him, and he\'s not conflicted. He knows exactly who he is. He knows his place in the world. He\'s fearless...he falls in love, but he doesn\'t change as a person...He makes his choice to die for the woman he loves, and he\'s at peace with that."

opened on Dec. 19, 1997, had "always played very complicated characters who have very deep flaws," notes Sanchini. And after starring in films like

, for which he earned his first Oscar nomination, playing Jack "almost seemed, I think when he first looked at it, too easy."

"Jim would be the first to tell you," Sanchini says. "It\'s like, \'I interviewed Leo for 15 minutes, and he interviewed me for three months!\'"

With Winslet, who was 22 when the movie came out, it was the other way around. "She\'d read the script, she came out to meet us, she sent Jim roses and signed the card, \'Rose Winslet,\'" Sanchini recalls with a laugh. 

"Kate is like that," she says. "When Kate loves something, when Kate\'s passionate about it, she is not one to play hard to get. She tells you how it is, and I love that about her."

And just as Winslet knew she wanted to play Rose, she knew that DiCaprio had to be Jack. Sanchini recalls the actors "doing an informal reading together" and watching as "they got to be fast friends."

"We all knew there was something special there," she says. "But afterwards, Kate said to us, \'Whether you cast me or not, you\'ve gotta cast him.\' He was just the guy."

Eventually, DiCaprio realize that "playing a character like Jack, who doesn\'t have any obvious stuff to hide behind...was a challenge in and of itself," Sanchini says.

But casting the film\'s star-crossed lovers was just one piece of the Titanic-size puzzle.

For Cameron, whose real-life fascination with shipwrecks inspired him to write the film, it was imperative that the movie be as historically accurate as possible. To help with this, Titanic researcher and author Don Lynch was brought on as the historian for the film. 

"In the very beginning, I went through the whole treatment with Jim," Lynch tells E! News exclusively. "Because his questions were, \'Well, if I have Jack and Rose here, and I want them here, can they get there easily without having to climb three flights of stairs and going the length of the ship?\'"

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Lynch was also on hand to consult with Cameron on logistical matters in the plot line, such as how to get third-class Jack into a first-class tuxedo when Rose\'s fiancé reluctantly invites him to dinner. 

"One of [Cameron\'s] questions was if there was some kind of men\'s shop on board like there are today on some ships," says Lynch. "And I said, \'Well, no, there were no stores,\' but it was my suggestion to have the unsinkable Molly Brown [played by Kathy Bates] sort of take Jack under her wing...and she had a son that age, so I said to Jim, \'Just say that Molly Brown is bringing a tuxedo home for her son [and she loans it to Jack].\' So you know, that\'s what he did—he wrote that into the script."

It was "a little loose that Jack got to come to dinner," says Lynch, "because classes were segregated, and especially so for health reasons." So to keep this plot line historically kosher, "[Jack] ended up having to sneak up over the railing to get into first class."

As for the actual setting of that dinner scene? It was meticulously accurate—right down to the tableware. "We recreated all the china and all the fabrics [from the real ship]," says Sanchini, "and they made replicas of the furniture."

20th Century Fox also rebuilt one entire side of the ship to full scale—something Sanchini says no one would do today. "It wouldn\'t even be economical or efficient to do moviemaking on that scale these days," she says, citing the rise of digital technologies. 

"It was...maybe not the last, but one of the last of the big builds," she says, "and there is something transportive about doing that...just to be there on this massive deck and walking that promenade, I have to believe it contributed to [the actors\'] tremendous performances."

Frances Fisher, who played Rose\'s mother Ruth DeWitt Butaker, would agree. "I had never seen anything quite like it," she tells E! News exclusively.  "I\'ll never forget the first time I drove over the rise to get to the studio...and I looked over on the right and saw the ship lit up for the first time, and it looked as if a real ship had been docked on the shore."

"When we shot the dock scene—you know, when we arrive in cars at the beginning, I felt as if I was there," Fisher adds. "As far as you could see there were background players all dressed in period costumes—down to the last person in the last row of anything. It was as if we\'d gone back in time."

There were, though, some comical reminders to bring the cast and crew back to present day reality. One that particularly stands out to Fisher is (spoiler alert, although it\'s been 20 years) is from the moment when Rose has to say goodbye to Jack. "The scene of Kate and Leo hanging off the door—and all the dead bodies covered in ice and floating [around them]...," the actress recalls.

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Fisher, who wasn\'t in the scene but came to set to watch it being filmed, still chuckles at the memory. "They\'d call for lunch, and then all these dead bodies would stand up and make their way over to the side of the tank, and walk up the stairs," she says with a laugh.

"They had to go really slowly," she adds, "because they were in period costumes, and they were waterlogged! They\'d...go outside and stand in line to get their lunch, and some of them would sit in hot tubs. But it was the funniest sight, because they had all this fake ice on their faces and blue lips!"

She wasn\'t the only one who saw the hilarity in moments like this. Fisher remembers DiCaprio and Winslet not just as "extraordinarily talented actors," but as "wonderful human beings with senses of humor."

"[Their] chemistry was obvious to all of us," she says. "The whole cast had that...It was a wonderful experience—it really, really was."

TAGS/ Titanic , Leonardo DiCaprio , Features , Apple News , Exclusives , Kate Winslet , James Cameron , Movies , Entertainment , Top Stories

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