Warner Bros.
"I hope it's an introduction [of the Joker] ... and not the end!" he told the Toronto Sun (via Heroic Hollywood). "Because I could easily just play the Joker a couple more times and then retire. Because it's so fulfilling and so creative and it's so imaginative. It's really difficult to think about doing anything else!"
In fact, Leto wants his Crown Prince to go up against Ben Affleck's Dark Knight.
"I think it would be incredible to see Batman and the Joker go head-to-head!" Leto said. "This Batman and this Joker. I mean, I don't know, that might be too much! But that would be fun."
It has been confirmed that Affleck is writing a standalone Batman movie that he will also direct and star in.
Affleck as Batman is also supposedly in "Suicide Squad," so maybe we'll see the two do battle sooner than that.