Based on new set photos from Birds of Prey (and the Fantabulous Emancipation of One Harley Quinn), the Joker might be also be appearing in the film - and he could be played again by Jared Leto. In the 2016 DCEU film, Suicide Squad, Leto starred as Batman’s nemesis alongside Margot Robbie as Dr. Harleen Quinzel aka Harley Quinn. For Birds of Prey, Robbie will reprise her role in the eighth DCEU franchise film.
Directed by David Ayer, Suicide Squad features an ensemble cast including Leto, Robbie, Will Smith as Deadshot, and Viola Davis as Amanda Waller. Set in the aftermath of Superman’s death, the film details the formation of Task Force X, which is assigned to engage in high-risk government missions. Produced for $175 million, Suicide Squad earned over $746 million at the box office, thus building hype for a follow-up film starring Robbie. Aside from the financial success, Suicide Squad also become the first DCEU film to earn an Academy Award, winning for Best Makeup and Hairstyling. In November 2016, Bumblebee writer Christina Hodson was hired to write Birds of Prey, and Cathy Yan was brought on to direct in April 2018. Birds of Prey began filming in January 2019.
On Twitter, DC Universe on Film posted Birds of Prey set photos that tease a possible return of The Joker. The collective images feature Robbie as Harley Quinn as she carries a crate of her personal items (including a baseball bat) in two images, and in another, more celebratory photo, she's carrying a tray of drinks. In the fourth image, Robbie’s character appears to be catching an wig that a man resembling The Joker is throwing to her from the second floor, seemingly because they've split up and The Joker is kicking her out. Conveniently, The Joker’s face is mostly covered in the set photo, so it isn't clear if that's Leto or a stand-in. However, Leto did recently tease a return as The Joker by sharing the clown emoji on his Snapchat account.
As of the moment, Leto’s involvement in Birds of Prey hasn’t been confirmed. In addition, he’s currently filming Morbius in London, based on the original Marvel Comics character. Still, that doesn't necessarily mean he couldn't make a quick trip to the Birds of Prey shoot in Los Angeles and film a small cameo. And even if the movie is using a stand-in on set, it's possible they could film close-up shots and record ADR at a later date. Either that, or Birds of Prey will present the scene in a such a way that it's never revealed exactly who is portraying The Joker - especially if the scene in question is minor one.
Since appearing in Suicide Squad, Leto has only appeared in two feature films, Blade Runner 2049 and The Outsider. In 2018, his band Thirty Seconds to Mars released their fifth album, America. Meanwhile, Joaquin Phoenix recently finished production for Warner Bros' Joker, in which he also plays a version of DC Comics’ famous supervillain. That film isn't connected with Birds of Prey or any other DCEU film, so Phoenix playing a version of The Joker doesn't rule out a return for Leto as the deranged Clown Prince of Crime.
Source: DC Universe on Film, Jared Leto