Margot Robbie thinks' Leonardo DiCaprio's 'Titanic' death scene was the "biggest controversy in modern cinema"

While promoting their new film 'Once Up a Time in Hollywood', Margot, 29, and Brad Pitt, 55,couldn't resist poking fun at their co-star Leonardo, 44, and questioned whether his character could have avoided death by squeezing on to the door at the end of the movie and insisted he should have spoken up at the time.

In an interview with MTV News, the stars were asked: "Biggest cinema controversy of all time, could Jack have fit on that door?"

'Suicide Squad' star Margot immediately responded: "I thought it. I remember bawling my eyes out when I was a girl."

Leonardo quickly replied: "I have no comment."

Brad weighed in: "That is funny... Well, I'm gonna go back and look now. Shoot!"

Margot joked: "That is the biggest controversy, I think, in modern cinema."

Brad then teased: "Could you, could you have squeezed there? You could've, couldn't you?"

Margot added: "Did you mention it at the time? Were you like, 'Should we make the door smaller?"

Leonardo refused to comment but was chuckling, prompting Brad to reply: "It's movie magic my friend, movie magic."

Despite Margot and Brad's confusion, Leonardo's 'Titanic' co-star Billy Zane - starred as Winslet's arrogant fiancé Cal Hockley - previously confessed he understood why Jack had to die in the film.

He said: "Your hero had to die. I don't know what else would have done it. It had to happen."

And the director himself previously insisted he'd made an "artistic choice" to kill Jack and couldn't understand why it's still being spoken about now.

He said: "The answer is very simple because it says on page 147 [of the script] that Jack dies. Very simple.

"Obviously it was an artistic choice, the thing was just big enough to hold her, and not big enough to hold him ... I think it's all kind of silly, really, that we're having this discussion 20 years later.

"But it does show that the film was effective in making Jack so endearing to the audience that it hurts them to see him die. Had he lived, the ending of the film would have been meaningless ...

"The film is about death and separation; he had to die. So whether it was that, or whether a smoke stack fell on him, he was going down. It's called art, things happen for artistic reasons, not for physics reasons."