The Biggest Fan Theories About Joker: Folie à Deux

One of the most highly anticipated movies hitting theaters in 2024 is the sequel to the award-winning breakout hit "Joker" –- currently titled "Joker: Folie à Deux." Although specific plot details have been kept secret, it's known that the film will continue the story of Arthur Fleck aka Joker (Joaquin Phoenix) and put a fresh musical spin on his brand of madness. However, he won't be alone this time around as Lady Gaga will co-star as her own version of Harley Quinn. Together, these two will cause chaos and mischief across Gotham that'll likely spark another rebellious effort from Joker's band of anarchist clowns.

Ever since "Folie à Deux" was announced back in 2022, fans have been speculating what the next chapter of Arthur's story could entail. Will we finally see the early days of Batman? Will other iconic DC villains make their debut in this universe? Is this all simply going to be a strange fantasy taking place in Arthur's mind? Despite there being minimal information about what's actually going to happen in the movie and no trailer yet, fans have been putting forth their best guesses as to where they think "Folie à Deux" will go. So let's look at some of the best theories for "Folie à Deux" that fans are sharing.

With Arthur Fleck creating quite the stir in Gotham and inspiring others to join his violent rebellion, it's possible that someone is now taking up his mantle while he's locked away. Maybe this follow-up story will see Arthur not only face the fallout of his actions, but also deal with a new Joker who's trying to usurp his power and influence. At least, that's what Reddit user u/AwfulMurray thinks could happen in "Joker: Folie à Deux." "I would prefer that a second Joker emerges and gains more popularity and Arthur becomes consumed with envy seeing him take his spotlight," the user wrote in r/Joker. "Then the new Joker makes fun of him just as all the others did and his life becomes a tragedy once more." 

The user also suggested that Leonardo DiCaprio would be a stellar choice to play this potential second Joker (back in 2017, DiCaprio's name was in heavy circulation for the part). However, this opportunity could allow the heavily fan-casted Willem Dafoe to play his own iteration of the Joker as well. Dafoe even said on "The Tonight Show Starring Jimmy Fallon" that he would love to play a version of the Joker, possibly an imposter.

It's a concept that excellently continues Arthur's arc from the first film and puts him in a complicated yet compelling position. While the character might initially be ecstatic to not feel completely alone anymore, the eventual betrayal would force him to go on a fulfilling reflective journey. This idea embodies that classic narrative framework of someone dealing with the monster they create — a common theme in many Batman stories.

The biggest addition to "Joker: Folie à Deux" is the introduction of Harley Quinn and her budding connection with Arthur Fleck. However, she could be much more than a protégé or love interest for Arthur. One theory, circulated by the podcast "The Weekly Planet" in their (scatologically themed) hot scoops segment, contends that the sequel will be told from Harley's perspective. Fans have expressed interest in this possibility and how it meshes with the promised musical elements of the film, with Reddit user u/SpaceZombie13 saying in a discussion in r/Batman, "If the sequel is from Harley's perspective as she's falling in love with Joker, it will make perfect sense to have random song-and-dance numbers."

While "Folie à Deux" is a definitive "Joker" sequel, it's not that far-fetched to hypothesize that Harley's perspective will be a pivotal component of the story. After all, Harley has risen in popularity amongst DC's vast character roster over the last few years. The film could offer a fresh perspective on their abusive relationship. "Exploring the toxicity of the relationship from Harley's POV and her descent into insanity because of him could definitely make for a good sequel," wrote another user, u/cbekel3618, in a thread on r/DCEUleaks. "I feel like this movie is a great chance to fully explore how unhealthy the Joker/Harley dynamic is." These users could be onto something with their theories, and "Folie à Deux" may stray from Arthur's perspective more than we expect.

Although the first film shows Arthur Fleck turning into his Joker persona after suffering years of personal tragedy, mental illness, and societal mockery, the character's origins are never that cut and dry. The idea of the Joker not having a definitive origin story like most comic book characters has always been intentional, as it maintains his sense of mystery.

Redditor u/andrewginzberg theorizes in r/Batman that the Joker having multiple backstories could be what "Joker: Folie à Deux" is all about. "What if the 2nd Joker movie isn't a sequel," the user wrote. "What if instead, it is another joker origin story. It's all still from Joaquin Pheonix's character POV still, but completely new reasons and different events unfold that leads to him taking on the joker persona." They even suggest that Joker's name might not be Arthur at all. "I hope it's another Joker origin story as part of a trilogy of Joker origin stories," said user u/2DamnBig in a thread about the film in r/TwoBestFriendsPlay. "We got the Comic, now we just need Red Hood and the Mobster," they said, referencing various Joker iterations from the comic books. This theory could be an interesting way to connect to the character's unique lore and turn a standard franchise into an innovative anthology.

With Harley Quinn and Joker coming together in this sequel, it's fair to assume that they will have a romantic bond similar to most of their depictions in the comics. Now, a tumultuous relationship between Harley and Joker could be all that comes from them uniting in "Joker: Folie à Deux." However, there's one theory that takes a more ambitious stance on where their fated connection could lead them.

Reddit user u/MySockHurts questions if Harley and Joker's blossoming romance could result in a storyline where Harley and Joker have a child together. The theory ties to multiple storylines throughout DC history where the Joker and Harley have a kid. 

For instance, in the animated film "Batman Beyond: Return of the Joker," the criminal couple kidnaps Tim Drake and tortures him until he becomes their twisted son. In another story, Harley had a child with him and their spawn eventually turns into a murderous psychopath just like his father. There's even another Batman villain named Anarky who is said to be Joker's son at one point. So could "Folie à Deux" be setting up an arc about Harley and Joker's kid to develop further in a future film? Possibly, but it depends on how Joker and Harley's shared story plays out.

Warner Bros. and DC are doing a lot with Batman on the big screen lately. Along with Matt Reeves continuing his film series with Robert Pattinson as the Caped Crusader, James Gunn is also working on a new version of the Dark Knight for his revamped DCU. Still, there's clearly some larger world-building happening in the "Joker" movies, and maybe it'll allow other Batman villains to appear in "Folie à Deux."

Reddit user u/Vigi1antee theorized in r/Batman that since Arkham Asylum will be the film's main setting, more grounded members of Batman's rogues' gallery could surface, specifically Victor Zsasz, Calendar Man, and a pre-Scarecrow Jonathan Crane. Other fans pointed out an Easter egg in set pictures that suggests Harvey Dent is coming to Todd Phillip's Joker-verse. In r/DC_Cinematic, user u/LostintheSecrets opined that since the picture only includes the surname "Dent," "It's most likely referring to Harvey Dent's dad, Harvey and Batman are usually the same age range and as we saw in the first one Bruce is still a kid in this universe. So unless in this universe all of Batman's villains are way older than him, it's not Two-Face."

If "Folie à Deux" ends up including more of Gotham's most vile and corrupt baddies, then the likelihood that other origin films will be made is greater than ever. Maybe we'll finally get fresh takes on fan favorites like Two-Face, Mr. Freeze, or maybe even Poison Ivy. We're already seeing that Warner Bros. is interested in letting more villain-focused stories be told — as Reeves' Batman universe has the "Penguin" TV series on the way — so maybe "Folie à Deux" will set the stage for other villains to get their time in the spotlight.

While certain aspects of "Joker" are directly linked to characters and plot threads from DC Comics, it's well noted that director Todd Phillips' vision for "Joker" was inspired by films like "Taxi Driver" and "The King of Comedy." Now, one fan thinks that "Joker: Folie à Deux" could take a page from another classic film — "One Flew Over the Cuckoo's Nest." Reddit commenter u/DarthVaderIsMyWaifu postulated in r/Movies that "Folie à Deux" could mix plot elements of "One Flew Over the Cuckoo's Nest" with the sequel's more asylum-focused story. "Just make it 'One Flew Over the Cuckoo's Nest' Arkham edition with Joker rallying the patients against the cruel overseer Professor Strange," the user said.

The callout for villain Hugo Strange to be a sadistic and cruel version of Nurse Ratched (Louise Fletcher) is honestly perfect and the concept flows with the first film's ending perfectly. After all, Arthur Fleck's arc is already going in the right direction for his next chapter to pay homage to the eerily similar film. Just as Randle McMurphy (Jack Nicholson) did in "One Flew Over the Cuckoo's Nest," Arthur could inspire other patients to rebel against the staff and turn one of their own — Harley Quinn in this case — against their superiors. It would be excellent for a follow-up story for Arthur and a loving tip of the hat to an all-time great film.

One of the more basic theories that fans have for "Joker: Folie à Deux" is that the movie could be a straightforward adaptation of a popular story featuring Joker and Harley Quinn. Redditor u/JJLong5 said in r/Movies that the film could reuse the plot of Paul Dini's 1994 one-shot graphic novel "The Batman Adventures: Mad Love." In the story, Harley recounts her origins as a psychiatrist in Arkham Asylum and goes through a rocky relationship with Joker that makes her question her love for him. By the end, she decides to leave her life of crime behind but is unfortunately pulled back under Joker's control again. Other fans praised that the film seemed to be taking inspiration from "Mad Love": user u/RefrigeratorPerfect said in r/Joker argued, "A mad love story between Joker and Harley could be really sophisticated." In r/Batman, u/Scared_Bobcat_5584 said, "Confused but curious about Joker 2, I didn't think it NEEDED a sequel, but Mad Love makes sense for where Joker left off."

"Mad Love" was already adapted for an episode of the animated series "The New Batman Adventures." But the upcoming sequel could rework the narrative for a live-action version that continues Arthur's arc from the first film. Frankly, using "Mad Love" as the backbone for "Folie à Deux" could be a great way to delve deeper into Arthur's psyche and explore manipulative parts of his Joker persona. If "Folie à Deux" takes inspiration from "Mad Love," it could make for a simple but intriguing look into one of the most complex relationships in comics. Plus, it has all the necessary pieces in place — well, aside from Batman, of course.

Although the first film introduces Bruce Wayne (Dante Pereira-Olson) as a young boy who suffers the horrific death of his parents, many viewers were left wondering if we'll ever see Bruce grow up to become Batman. Reddit user u/Spyro08642 made the case for "Joker: Folie à Deux" to be where Bruce steps into his hero role — but only on one condition. "They could maybe do a bit of a time jump and introduce Batman," the user said. Elsewhere, on r/DC_Cinematic, u/BorderDispute predicted, "Bruce Wayne will have a larger role than in the first movie, he's a huge part of the Joker mythos. There could be a time jump and we see an older Bruce who understands that Joker indirectly caused the death of his parents and is vengeful." In theory, a flash-forward would make it easy for Batman to suddenly appear. In actuality though, it creates many complications.

Pereira-Olson is in his teens, so producers would have to find a new actor to play Bruce if they were planning on bringing Batman into the fold. Characters like Arthur would have to become much older for it to make sense if Todd Phillips is keeping continuity with most "Batman" stories. Also, so many years would pass that a lot of history and world-building in Gotham would have to be covered to make up for lost time. A time jump could honestly cause a lot of problems, but it might be the only logical way for Batman to ever appear in the "Joker" films if it's going to happen.

Arguably the most shocking twist in "Joker" is the reveal that Arthur's relationship with his neighbor, Sophie (Zazie Beetz), was completely in his head. Because of that, some fans think that "Joker: Folie à Deux" will take the fantasy elements of that moment much further. One Redditor posted in r/DC_Cinematic about how Arthur's fantasies could work incredibly well with the film's musical approach. "I feel like it would be very cool to see every 'musical number' be Arthur just dancing with invisible people and to the sound of music playing in his head," they wrote. Other users have run with a similar idea: User u/jmster109 wrote in r/comicbookmovies that the only way they would accept the musical elements of the sequel is if they were rooted in dreams or fantasy scenes. User u/DogDrivingACar expressed the same idea in r/Letterboxd, saying, "I'm imagining something similar to Dancer in the Dark, a dark/sad story interspersed with fantasy musical numbers."

To be fair, the whole idea of Joker's relationship with Harley just being a fantasy runs the risk of repeating plot points from the first film. But, the connection between musical sequences and Arthur's fantasy opens many possibilities for ways to delve deeper into Arthur's slow-loosening grip on reality and create a more engaging build-up of Arthur and Harley's romance.

What's more trending nowadays than the multiverse, right? Just within the last few years, audiences have traversed many stories that deal with characters interacting with parallel worlds or different versions of themself. There have been Sony's "Spider-Verse" films, the Oscar-winning "Everything Everywhere All at Once," and let's not forget the ongoing ups and downs of the MCU and DCU getting their respective cinematic multiverses in order. Now, though, some fans are arguing that "Joker: Folie à Deux" should have its own "Multiverse of Madness" moment. Reddit commenter u/silentlycold said in r/boxoffice that the sequel should feature cameos from previous Jokers — like Jack Nicholson's and Jared Leto's incarnations of the character.

While the thought of Arthur Fleck interacting with the DC multiverse is full of wild possibilities, it's a little too sci-fi for the grounded and gritty nature both "Joker" films present. But there's still a way for past Jokers to appear alongside Arthur — through his fantasies. If Nicholson and Leto reprised their roles, it would be fun to see them act as different voices within Arthur's head. Conversations about their distinct worldviews would make for a riveting and exciting dissection of the various Jokers' ideologies. Audiences would go nuts in the theater.