'Joker:' Robert De Niro & Joaquin Phoenix's Behind-The-Scenes Disagreement Explained

There was certainly some tension between Joaquin Phoenix and Robert De Niro. The former may have been the movie's titular star, but the latter was still one of the biggest stars in the history of Hollywood. 

De Niro wanted to get together for a read-through prior to the start of production. Phoenix, on the other hand, is not a fan of the customary read-through process. Todd Phillips had to find a way to deal with the vastly differing preparation styles. He recalls: 

Bob called me and he goes, "Tell him he's an actor and he's got to be there. I like to hear the whole movie, and we're going to all get in a room and just read it." And I'm in-between a rock and a hard place because Joaquin's like, "There's no f**king way I'm doing a read-through," and Bob's like, "I do read-throughs before we shoot, that's what we do."

The Hollywood veteran got his way, and a read-through took place at De Niro's office in New York City. However, even if Phoenix attended the meeting, he reportedly mumbled and sulked through much of the process. Afterwards, the Taxi Driver actor asked to speak privately to Phoenix, who initially denied the request.

The method actors reportedly talked it out. Phillips said that De Niro cupped Phoenix's face with his hands and even smacked him with a kiss on the cheek. De Niro assured him, "It's going to be okay, bubbeleh."

De Niro later said of Phoenix, "Joaquin was very intense in what he was doing, as it should be, as he should be."

There is a medical condition called pseudobulbar affect (PBA). It causes its sufferers to laugh or cry (or both) uncontrollably. It can lead to weeping and often has absolutely nothing to do with how the person is actually feeling. 

In Joker, Arthur Fleck suffers from PBA. He even has to carry a card with him to let people know about his condition that reads, "Forgive my laughter. I have a condition." When Fleck is nervous or in a stressful situation, he produces painful, cacophonous laughter. 

Fleck's laughter is off-putting and awkward, far from the pleasant jolliness typically associated with laughing. It makes the people around him uncomfortable and perhaps even scared. In order to prepare for the role, Phoenix studied videos of people affected by PBA. 

"I started [with the laugh]," Phoenix said. "I watched videos of people suffering from pathological laughter, a neurological disorder that makes individuals laugh uncontrollably."

Somehow, Warner Bros. knew to just let Todd Phillips and Joaquin Phoenix do their thing. Producers handed Joker filmmakers $55 million and basically stepped off - a rarity in modern-day movie production.

Phillips was constantly tinkering with the film's script. Actors had to adjust and improvise to accommodate the daily script changes. The madness definitely suited Phoenix, who grew more and more improvisational as his character shifted from Arthur Fleck into the Joker. 

Phoenix more than earned his Academy Award for best actor by expanding what was written on the page and taking Joker to a new height of surreal insanity. The film's cinematographer Lawrence Sher discussed the one-take scene when Phoenix unexpectedly climbs into the refrigerator:

While some scenes were very planned out, like when he’s in the phone booth or walking up the stairs, others had no plan at all. When he climbed in the refrigerator, we had no idea he was going to do that. We set up two camera positions, and Joaquin just thought about what he would do if he was a massive insomniac. Again, we lit it so he could go anywhere, and the first and only time he did it, we were mesmerized. I remember thinking, "What is he doing? Did he just crawl in the fridge?" It was as fun and weird for us to watch it, too.

Fleck's bathroom dance following his subway murder spree was also improvised. Sher explained:

Joaquin created that whole dance and, after the success of that scene, we started creating more moments like that. Like when he's playing with the gun and fires it into the wall. All we knew was that he'd fire the gun into the wall at some point, but we never planned when or knew that he'd stand and have that conversation with himself and begin dancing. We just had two cameras in there and let it happen, which became a major part of how we did a lot of things.

What happens when two method actors work together on the same movie? Chances are, if their characters are not friendly in the film, then the actors who portray them won't be friendly off-screen, either. 

Robert De Niro plays talk show host Murray Franklin in Joker. The longtime TV personality is not happy that the latest media sensation Arthur Fleck will be on his show and lets everyone know exactly how he feels. Franklin is one key cog in Arthur's collapse into a ruthless sociopath. The actors only have one significant scene together in the movie, and it's a shocking one.

It shouldn't come as a surprise that both Phoenix and De Niro saw absolutely no reason to converse with one another unless the cameras were rolling.

"I didn't like to talk to him on set," admits Phoenix. "The first day we said good morning, and beyond that, I don't know that we talked much."

"His character and my character, we didn't need to talk about anything," added De Niro. "We just say, 'Do the work. Relate as the characters to each other.' It makes it simpler, and we don't [talk]. There's no reason to."

Joker fades to black, the story is over, and the ending is clear.

Not even close.

The movie's ambiguous ending has sparked debate across the internet and with movie critics. We know that Arthur Fleck is delusional, we know that his mental state is questionable, and we know that the film ends with Fleck as a patient in Arkham State Hospital. The audience ultimately realizes that they don't know how long he's been there or how much of the story that they've seen actually happened. Fleck is the definition of an unreliable narrator.

Todd Phillips purposefully left his film's ending ambiguous. Does Fleck become the Joker that comic book and movie fans have seen throughout the past several decades? 

Phillips addressed the movie's open ending in a behind-the-scenes featurette called "Joker: Vision & Fury." 

"There's many ways to look at the movie. He might not be Joker. This is just a version of a Joker origin," said Phillips. "It's just the version this guy is telling in this room at a mental institution. I don't know that he's the most reliable narrator in the world, you know what I'm saying?"

Phoenix disagrees with the writer's assessment. He believes that Arthur is the actual Joker. "But I don't know. It's just my opinion." added the actor.

The Marvel Cinematic Universe links over 70 superhero characters, from Iron Man to Spider-Man to Black Widow. Many of those titans team up in Avengers movies.

Warner Bros. has not had the same success with its DC Extended Universe, as seen with the middling Justice League and Batman v Superman. In fact, the media company has even shied away recently from the whole concept of the DCEU in favor of the good ol' fashioned standalone comic book superhero movie. 

Todd Phillips wanted to make sure his Joker never battled with Robert Pattinson's Batman or some odd meta-twist on Jared Leto's Joker from Suicide Squad. The writer-director set the year of Joker in 1981 to ensure his unique character would remain a standalone villain that is free from any possibility of a crossover event.

"But the time for me... one reason was to separate it, quite frankly, from the DC universe. When I pitched to Warner Brothers and handed the script in, to sort of make it clear - this isn't f**king with anything you have going on. This is like a separate universe," warned Phillips. "So much so, it takes place in the past, before everything else."