“The worst part of having a mental illness is people expect you to behave as if you don’t,” writes Arthur Fleck (Joaquin Phoenix), who is soon to be transformed into the iconic Batman villain, Joker. The teaser of Todd Phillips’s Joker, which was released on Wednesday, introduces the man behind the maniacal villain of Gotham City. Co-starring Robert De Niro, Zazie Beetz (Deadpool 2), Brett Cullen and Brian Tyree Henry (If Beale Street Could Talk), the film will be released on October 4.

Arthur Fleck is a failed stand-up comedian who makes a living by dressing up as a clown in Gotham City in 1981 – “when the city was tough”, as described by a cast member, Shea Whigham. Fleck has to deal with bullying and beatings when he is not being driven round the bend by the city’s chaos and his mental health problems.

By the end of the teaser, set to operatic music, Fleck has transformed into the popular version of Joker, as we have known from his multiple iterations in comic books, films, television series and video games.

Joker (2019).

Phillips’s Joker is a standalone movie. It is not a part of the DC Extended Universe that comprises interconnected productions based on DC comic books, starting with the Superman movie, Man of Steel, in 2013.

In an interview with Collider in 2018, Phoenix, who earlier passed on the opportunity to play Marvel character Doctor Strange, talked about his interest in a low-budget character study of the comic book villain: “I think, underneath the excitement of these films, and the size of them, there are these incredible characters that are dealing with real life struggles.”

Producer Warner Bros officially described Joker as “an exploration of a man disregarded by society [that] is not only a gritty character study, but also a broader cautionary tale”. The story and screenplay are by Phillips and Scott Silver (8 Mile, The Fighter).

Robert De Niro plays Murray Franklin, a talk show host. Speaking to Indiewire recently, De Niro confirmed that his character is connected to his 1982 film, The King of Comedy, in which he played a failed stand-up comedian obsessed with another comedian (Jerry Lewis).

Zazie Beetz plays a single mother whom Fleck is attracted to. Bill Camp (The Night Of) and Shea Whigham play police offers who are investigating a crime that takes place in the beginning of the film. Brett Cullen plays Gotham City billionaire Thomas Wayne, the father of Bruce Wayne/Batman. A young Bruce Wayne will be seen in the film. According to reports, the portrayal of Thomas Wayne will be less sympathetic than previous versions.

Joaquin Phoenix as the Joker. Courtesy Warner Bros.

Phoenix is the fourth actor to essay Batman’s archenemy after Jack Nicholson in the Tim Burton films, Heath Ledger in The Dark Night, and Jared Leto in Suicide Squad.

Cesar Romero played Joker in the campy 1960s Batman television series. Romero’s Joker was a silly and humorous take on the character. His Joker sparred with Batman and Robin in misadventures, such as the one in which Joker and Batman participated in a surfing competition.

Cesar Romero's Joker in Batman (1966-1968).

Jack Nicholson’s Joker in Tim Burton’s blockbuster Batman (1989) was a comparatively darker portrayal, but not as dark as the one by Heath Ledger in Nolan’s The Dark Knight (2008). However, Nicholson’s Joker did steal the movie from Michael Keaton’s Batman.

Jack Nicholson and Michael Keaton in Batman (1989).

Following the success of Batman and its sequel, Batman Returns (1992), Warner Bros bankrolled Batman: The Animated Series, which had complex characters, an aesthetic inspired by film noir, and generous lashings of violence. Mark Hamill’s voice acting (and crazy laugh) as Joker is considered by Batman fans as one of the best takes on the character. Hamill went on to voice Joker in animated productions, such as the acclaimed Batman: Mask of the Phantasm (1993), and Batman-themed video games.

Mark Hamill's Joker.

Nolan’s cerebral The Dark Knight strayed far from the comic books, and made Joker a symbol of the debate over vigilante justice in post-9/11 America. Heath Ledger won a posthumous Academy Award for the Best Supporting Actor.

Heath Ledger's Joker.

Jared Leto’s take in David Ayer’s Suicide Squad (2016) was a mild update on Ledger’s performance. Leto’s performance was drowned by the critical backlash to Suicide Squad. Additionally, reports of Leto tormenting his co-actors in the name of method acting did not fetch the Oscar-winning actor any brownie points.

Jared Leto's Joker in Suicide Squad (2016).

In the ongoing television series Gotham, Cameron Monaghan plays Jerome Valeska, a forerunner of the character. At the end of season four, it is revealed that Jerome has a disgruntled twin, Jeremiah, who is an engineer. After Jerome dies, Jeremiah gets exposed to a gas that bleaches his skin white and drives him insane.

Cameron Monaghan's Joker in Gotham (2014-present).