But now we've got a proper look a Gotham City's Clown Prince of Crime, in two moody and menacing shots.
Released by Snyder to Vanity Fair, the monochrome stills sit in stark contrast to the lurid and colourful punk-esque Joker seen in David Ayer's Suicide Squad.
Read more: Snyder teases Joker pic
Speaking to the magazine, he said: “The Joker is really the only thing that I thought of in retrospect. But I will say that it was always my intention to bring Joker into that world.”
Snyder also reveals a couple of spoilers about how the Joker will be drafted into to his cut of the movie, having not been in the original.
He explains that Leto's Joker appears in a 'dream sequence' appearing as a 'psychic vision' by Ben Affleck's Bruce Wayne, after the villain Darkseid has ravaged the Earth.
Snyder goes on: “The cool thing about the scene is that it’s Joker talking directly to Batman about Batman.
“It’s Joker analyzing Batman about who he is and what he is. That’s the thing I also felt like fans deserved from the DC Universe. That is to say, the Jared Leto Joker and the Ben Affleck Batman, they never really got together. It seemed uncool to me that we would make it all the way through this incarnation of Batman and Joker without seeing them come together.”
Snyder also hints at discussing the tease from Justice League that Joker was responsible for killing Batman's sidekick Robin.
“I’d always wanted to explore the death of Robin,” Snyder added. “And if there ever was going to be a next movie, which, of course, there probably won’t be, I wanted to do a thing where in flashbacks we learn how Robin died, how Joker killed him and burned down Wayne Manor, and that whole thing that happened between he and Bruce.”
Snyder's cut is likely to be a very different movie to that which was released in cinemas in 2017.
The director was forced to step away during post-production, following the tragic death of his daughter, with Joss Whedon being drafted in to complete it.
But Whedon instead elected to re-shoot and add scenes, the final product being panned by critics and underwhelming at the box office.
Snyder was given the green light to re-cut his original version – with his own added reshoots – last year.
The new version – which will run to four hours and thanks to some choice language from Batman will be rated R – is set for release on HBO Max in the US on 18 March.
Details of the UK release are yet to be confirmed.
Watch: Snyder has no plans for more DC movies