Quentin Tarantino & Leonardo DiCaprio Explain Giving Rick Dalton Undiagnosed Bipolar Disorder In 'Once Upon A Time'

I don’t pretend to be any sort of actor. In fact, I am absolutely dreadful at that sort of thing. However, it makes complete sense to a layperson like myself that a really talented actor needs information about the person they’re portraying to give the most convincing performance. And in the case of Leonardo DiCaprio (a pretty damn fine actor by most accounts) and his character of Rick Dalton in “Once Upon a Time in Hollywood,” all it took was one little wrinkle to really give the role added depth.

Speaking in a new video from Vanity Fair, DiCaprio and ‘Once Upon a Time’ filmmaker Quentin Tarantino talk about one instance where the duo had to brainstorm to unlock something that was missing from the actor’s understanding of Dalton in the film. And in typical Tarantino fashion, the filmmaker took a page from Hollywood history.

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Tarantino discusses how they came to the conclusion to make Rick Dalton suffer from an undiagnosed mental illness after DiCaprio came to the filmmaker with an issue.

“In a very nice way, Leo would say, ‘Okay, all of that is well and good about all this minutia, [but] I need something to act,'” Tarantino said.

The filmmaker then looked at one of his favorite actors, Pete Duel, and told DiCaprio the story of his untimely demise. Duel, who famously starred in the Western series “Alias Smith and Jones,” committed suicide, with many believing it stemmed from his use of alcohol to self-medicate undiagnosed bipolar disorder. This knowledge gave DiCaprio all he needed to model Dalton after the late actor.

Tarantino explained:

“Now, we already had Rick a drinker, but the whole thing about undiagnosed bipolar and not knowing how that works, and the weird pendulum swings of emotion you would have … that became a really interesting thing that we thought Rick could deal through. And that gave Leo a good, solid ground in which to work and build a character and have a subtext going on inside of scenes that doesn’t have to revolve around the story of the scene.”

If you’ve seen the film, you know that Dalton’s ailment was never mentioned or even hinted at, other than DiCaprio’s masterful performance, with certain tics and outbursts. But with this knowledge, it does add a layer to the role that you may not have realized during your first viewing.

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Of course, there are those that would have liked the mystery to be preserved. Maybe you didn’t need to know about Rick Dalton’s undiagnosed bipolar to enjoy DiCaprio’s work in the film. That being said, it does make for good trivia to impress your friends with.

“Once Upon a Time in Hollywood” is in theaters now.