Image copyright Warner Bros Image caption Phoenix is seen sporting clown make-up in the Joker trailer

The first trailer for a new origin movie about iconic comic book villain The Joker has been released.

It shows Joaquin Phoenix undergoing a painful transformation from a decent chap into Batman's cackling nemesis.

Phoenix plays Arthur Fleck, a stand-up comedian who gradually loses touch with reality after a series of hardships.

The first trailer for Todd Phillips' film - out on 4 October - was premiered this week at the CinemaCon convention in Las Vegas.

"My mother always tells me to smile and put on a happy face," Fleck is heard telling his therapist.

"She told me I had a purpose... to bring laughter and joy to the world."

Phoenix's character is then heard asking: "Is it just me, or is it getting crazier out there?"

The Joker trailer goes on to show Fleck dancing with his mother, going on a date with a girl and laughing maniacally at a stand-up comedian.

It then takes a dark turn when he's labelled "a freak" and and attacked by men on the subway.

"I used to think my life was a tragedy," his Joker concludes. " But now I realise it's a comedy."

Image copyright Warner Bros

Image copyright Warner Bros

Image copyright Warner Bros

Twitter user Jeff Lowe said Phoenix met his criteria for a successful Joker by being "someone who can make it their own and unique."

He likened his interpretation to that of the late Heath Ledger, who won a posthumous Oscar for his performance in 2008's The Dark Knight.

Ryan Parker from the Hollywood Reporter said the trailer was "dark, unsettling and shows a man slowly breaking apart."

Brandon Katz from New York-based website Observer was equally sold, commenting Phoenix's beleaguered Joker looked "emaciated and disillusioned".

Jack Nicholson, Jared Leto and Cesar Romero are among numerous other actors to have played The Joker on screen.

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