Leonardo DiCaprio is keeping mum when it comes to the “Titanic” door debate, even if his “Once Upon A Time In Hollywood” co-stars Brad Pitt and Margot Robbie can’t seem to get enough.

The popular controversy revolves around the scene in the 1997 film in which Kate Winslet’s Rose clings to life atop a floating door while DiCaprio’s Jack stays in the icy water. For decades, fans have argued that both Jack and Rose could have fit on the door — 22-year-old spoiler alert — thus, preventing Jack from freezing to death and sinking to the ocean floor.

While promoting the upcoming Quentin Tarantino film with MTV, Robbie couldn’t help but wade into the debate.

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“Oh my gosh… I remember bawling my eyes out when I was a girl,” the 29-year-old Aussie actress says.

“I have no comment,” DiCaprio, 44, replies with a laugh as Robbie calls it “the biggest controversy in modern cinema.” Adds DiCaprio: “Ever.”

Even Pitt, 55, can’t get any answers from the “Titanic” star.

“Could you, could you have squeezed in there? You could’ve, couldn’t you?” he teases, receiving another “no comment” from his co-star.

But Robbie still has questions.

“Did you mention it at the time? Were you like, ‘Should we make the door smaller?'” she asks DiCaprio, who responds with a smile.

His “Titanic” co-star Winslet agrees with Robbie. “He could have fit on it! He could have fit on that door!” the actress joked back in 2017.

While Leo may not want to discuss it, “Titanic” director James Cameron addressed the fan theory earlier this year in a heated debate on BBC1’s “Movies That Made Me”.

“I’ve never really seen it as a debate, it’s just stupid,” Cameron said at the time. “There’s no debate. But if you really want to unearth all the dumbass arguments associated with it.”

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“I mean, let’s go back to, could Romeo have been smart and not taken the poison? Yes. Could he have decided not to bring his little dagger just in case Juliet might stab herself with it? Yes, absolutely. It sort of misses the point,” he said.

DiCaprio will likely not have to share a door in the ocean in “Once Upon A Time In Hollywood”, which opens in theatres on July 26.