Titanic Turns 25! James Cameron 'Can't Imagine' Movie Without Leonardo DiCaprio and Kate Winslet

Merie Weismiller Wallace/Paarmount Leonardo DiCaprio and Kate Winslet in Titanic

A quarter-century has passed since James Cameron's Titanic premiered in theaters!

25 years later, 1997's Titanic still stands tall as one of the highest-grossing movies ever made, and director Cameron, 68, recently told Deadline he "can't imagine that film" without its two leading stars in Leonardo DiCaprio and Kate Winslet.

"I think about that casting Leonardo [DiCaprio] and Kate [Winslet] in Titanic. Leo, the studio didn't want him; I had to fight for him," the director told the outlet during an interview about his career and his new movie, Avatar: The Way of Water.

"Kate really liked him," the director said of DiCaprio, now 48. "And then Leonardo decided he didn't want to make the movie. So then I had to talk him into it."

During the interview, Cameron noted that Titanic "wouldn't have been that film" if DiCaprio had decided not to take his role as Jack or if anything with the production had come together differently.

RELATED: James Cameron Says Leonardo DiCaprio Nearly Lost Titanic Role Over His Attitude in Audition

"You think at any one of those places, if that had really kind of frayed apart, it would have been somebody else and it wouldn't have been that film," he told the outlet. "And I can't imagine that film without him and without her."

Paramount Pictures and Twentieth Century Fox And... cut! Cameron directing DiCaprio and Winslet in a scene from Titanic. (The blade of Rose's ax was rubber.)

"So there's a fragility to the whole process, there's a fragility to success," Cameron added. "You change one element and it doesn't work."

In a video career retrospective for GQ published in November, the director spilled on casting DiCaprio as Jack for Titanic, which almost fell apart over the actor's poor attitude during auditions.

"There was a meeting with Leo and then there was a screen test with Leo," Cameron said, setting the scene. "The meeting was funny because I am sitting in my conference room, waiting to meet an actor. And I look around, and all the women in the entire office are in the meeting. They all wanted to meet Leo. It was hysterical."

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The filmmaker said the first meeting went well and DiCaprio "charmed everybody" so he was asked back for a read with Winslet, who had already been cast. It did not go as smoothly. At least, not at first.

Alamy Stock Photo

"So he came back a couple of days later, and I had the camera set up to record the video," Cameron recalled. "He didn't know he was going to test. He thought it was another meeting to meet Kate. So I said, 'Okay, we'll just go in the next room, and we'll run some lines and I'll video it.' And he said, 'You mean, I'm reading?' I said, 'Yeah.' "

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"He said, 'Oh, I don't read,' " Cameron continued. "I shook his hand and said, 'Thanks for coming by.' And he said, 'Wait, wait, wait. If I don't read, I don't get the part? Just like that?' And I said, '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.' "

DiCaprio reluctantly agreed to read and was indignant until the camera was rolling, Cameron claimed, but once he gave DiCaprio the go-ahead to read, the actor "turned into Jack."

"Kate just lit up, and they played the scene," the director said. "Dark clouds had opened up, and a ray of sun came down and lit up Jack. I'm like, 'All right. He's the guy.' "

Titanic is currently the eighth highest-grossing movie ever at the domestic box office. Top Gun: Maverick passed Titanic in August as it shot to the fifth-highest grossing movie of all time.

PEOPLE's new special edition, Titanic: Leonardo DiCaprio, Kate Winslet and the Making of an Epic Love Story, is available now wherever magazines are sold.