After years in the making, Warner Bros. Animation's adaptation of the classic Batman story "The Killing Joke" is finally on its way to being released. While an official release date has yet to be announced, "Batman: The Killing Joke" is expected to be released sometime in 2016, after the release of fellow DC Animated Original Movie "Justice League vs. Teen Titans." Concept designer Phil Bourassa, who has worked on the majority of DC's recent animated projects, revealed a piece of early concept art via his Instagram that shows just how long "The Killing Joke" has been in the works.

Bourassa's pair of Joker sketches date back to 2009 when he was collaborating with Bruce Timm on the animated adaptation of the classic Alan Moore/Brian Bolland story. As Bourassa's caption explains, the R-rated animated feature was put on hold after the R-rated, live-action adaptation of "Watchmen" underperformed at the box office. But many years of superhero success stories and the continued interest in the genre has, as Bourassa writes, allowed the mature "Killing Joke" to transcend "the previously assumed limitations of the genre."

In 2009 I started working on an animated adaptation of The Killing Joke under the supervision of legendary Animation artist Bruce Timm. Two weeks into the project we were told to stop development because The Watchmen had underperformed at the box office and WB had lost faith in R rated superhero movies. Happy to say that you guys are gonna finally get your animated Killing Joke adaptation in 2016. Apparently enough money has been made from superhero movies and adaptations of comics of every stripe that it now transcends the previously assumed limitations of the genre. It's a good time to be a comic geek! #dccomics #dcentertainment #wbanimation #killingjoke #joker #brianbolland #alanmoore #comics #animation A photo posted by Phil Bourassa (@philbourassa) on


As was reported back in October, it's even possible that the animated "Killing Joke" will get an R rating. Producer James Tucker previously said that they're allowed to make an R-rated film, but whether or not the film actually snags a mature rating remains to be seen.

In addition to a release date, the voice actors involved in "The Killing Joke" have not yet been confirmed. Mark Hamill is reportedly returning to voice the Joker and there are rumors that Kevin Conroy will reprise his role as Batman, but the WB has not made an official announcement regarding either casting.