This Is Us helmers Glenn Ficarra and John Requa, who direct and executive produce the hit NBC drama, are in final negotiations to take on the film that is a part of the studio's DC extended universe, Variety reported.
The film is being described as a criminal love story, an insider told The Hollywood Reporter, calling it "When Harry Met Sally on benzedrine."
Leto and Robbie portrayed The Joker and Harley Quinn in 2016's Suicide Squad. A sequel to Suicide Squad is also in development that will star Leto and Robbie as well. Robbie's Gotham City Sirens project with director David Ayer, that would bring Harley Quinn together with other Batman villains such as Catwoman and Poison Ivy, appears to be on hold for now.
News of the Joker and Harley Quinn standalone film comes after Warner. Bros. announced the development of a Joker origin film produced by Martin Scorsese and set to be directed by Todd Phillips who is also writing the script with Scott Silver.
The origin film will not star Leto as the Clown Prince of Crime and is being made under a new DC Comics film banner or label separate from the DC extended universe to allow the studio to tell unique comic book stories using different actors in the title roles.
Films under Warner. Bros. DC extended universe besides Suicide Squad include Man of Steel, Batman v Superman: Dawn of Justice, Wonder Woman and the forthcoming Justice League.