Watch: Joker teaser trailer shows first glimpse of Joaquin Phoenix as classic Batman villain

The first teaser trailer for the upcoming Joker movie has been released giving fans their first look at Joaquin Phoenix in the role of the classic Batman villain.

The Warner Bros movie is not connected to Christopher Nolan's hugely popular Dark Knight Batman franchise and is the start of a new origin story about how the Joker became the Clown Prince of Crime.

Ahead of the film's release on October 4, the chilling trailer shows Phoenix as the mild-mannered Arthur Fleck, a down-on-his-luck clown comedian from Gotham, struggling with life's hardships.

Hollywood star Joaquin Phoenix during filming in New York City for the movie Joker. Photo / Getty Images.

Viewers get a sense of the misery and bitterness that prompts Fleck's transformation through fleeting glimpses of him being robbed, beaten and humiliated on the streets and subway, while Phoenix's creepy voiceover asks: "Is it just me, or is it getting crazier out there?"

Directed by Todd Phillips, Joker also stars Robert De Niro as a TV talk show host named Murray Franklin, and Zazie Beetz (Atlanta) as Sophie Dumond, a single mother who appears to date Fleck.

Phoenix is the latest in a long list of actors to take on the role of the Joker, including the late Heath Ledger in Nolan's The Dark Knight, and Jared Leto in Suicide Squad.

Phoenix's Joker appears more in tune with Ledger's disturbing depiction, although his costuming looks inspired by Cesar Romero's classic 1960's Batman version.

Eagle eyed fans will also notice a brief encounter between the Joker and a young boy, with Phoenix's character reaching through an iron fence and using his fingers to stretch the child's face into a wide clown-like smile.

That kid is played by Dante Pereira-Olsen, who is starring as none other than Bruce Wayne, the boy who will grow to become the Caped Crusader, the Joker's arch nemesis.