DC Entertainment has a rich direct-to-video collection and it's looking to add "The Killing Joke" in July, according to executive producer Bruce Timm.

An adaptation of the 1988 graphic novel written by Alan Moore and illustrated by Brian Bolland, "Batman: The Killing Joke" will tackle one of the most acclaimed stories involving the Joker. Apart from being iconic, it is also undoubtedly one of the most controversial narratives, making it highly likely that the animated movie will be rated R.

In an interview, Timm talked about how the goal has always been to stick to the comic book as closely as possible. The producer said he's not allowed to talk about many things about the upcoming animated movie but he did say that they will be expanding on The Killing Joke. They are doing so because the 48-page story the comic book originally had did not provide enough source material to meet the requirements of a feature film.

"So we actually had to add a lot more story to it. Which is tricky. But I think we came up with a really good solution on how that worked," he said. "Killing Joke is a really tricky property ‘cause it's really bleak, but we made a decision early on that if we're gonna do it then we kinda have to just, you know, jump in and just do it."

Warner Bros. Animation Studios has not yet made any announcements about the animated movie's cast but Mark Hamill is reportedly on-board as the Joker. What Timm has confirmed, however, is that "Batman: The Killing Joke" is set for a world premiere at the San Diego Comic-Con, which will run from July 21 to 24.

In March 2015, a variant cover for Batgirl #41 took inspiration from The Killing Joke. It didn't sit well with fans, however, who used the hashtag #ChangeTheCover on social media to show their displeasure. The cover was canceled at the request of its artist, Rafael Albuquerque, but DC Entertainment also explained that the decision to pull it was also guided by the fact that it was inconsistent with the current direction the Batgirl books are taking.