The trailer begins with Arthur Fleck amusing a child on a bus, only to be told to stop by the boy's mother. From there, he begins his descent into madness before finally finding his smile as The Joker.
The trailer also heavily features Robert DeNiro's Murray Franklin, who's clearly Fleck's primary target. The trailer then comes to a close with Fleck requesting that DeNiro's Murray introduce him as "Joker" before he finally takes to the stage in full clown attire.
The film will see Fleck portrayed as a failed comedian trying to care for his mother. Eventually, the unrelenting cruelty of society compels him to turn to a life of crime and become the titular supervillain. Joker is said to be unlike any other comic book movie and, it will not adapt any previously established stories.
Directed by Todd Phillips, Joker stars Joaquin Phoenix, Robert De Niro, Zazie Beetz, Bill Camp, Frances Conroy, Brett Cullen, Glenn Fleshler, Douglas Hodge, Marc Maron, Josh Pais and Shea Whigham. The film arrives in theaters Oct. 4.