Snyder's black and white photo is blurry and keeps Leto's face hidden. The actor is holding up a joker playing card while wearing a rubber glove on his hand.
"Amazing character you have created. Honored to have our worlds collide. @DavidAyerMovies @JaredLeto," Snyder captioned the image while tagging Leto and Suicide Squad director David Ayer.
Ayer introduced Leto's take on the Joker in 2016's Suicide Squad. Leto's Joker had multiple tattoos, shaved eyebrows and a silver grill for his teeth.
Zack Snyder's Justice League will be the first time Leto appears as The Joker since Suicide Squad.
Zack Snyder's Justice League is coming to HBO Max on March 18. The film is a new version of 2017's Justice League that was handled by Joss Whedon after Snyder left the project following a family tragedy.
The new version will be Snyder's vision for the film and will feature new scenes and characters including Leto's Joker and all-powerful villain Darkseid.
The film also features Ben Affleck as Batman, Gal Gadot as Wonder Woman, Henry Cavill as Superman, Jason Momoa as Aquaman, Ezra Miller as The Flash, Ray Fisher as Cyborg, Amy Adams as Lois Lane, Diane Lane as Martha Kent, and Jeremy Irons as Alfred Pennyworth.