A long-rumored adaptation of Frank Miller and Klaus Janson's landmark 1986 miniseries The Dark Knight Returns finally may be in the works -- as an animated movie.

Citing "multiple sources," Bleeding Cool reports the project is already in the early stages of development, with the involvement of "several veterans of Batman toons past."

If true, The Dark Knight Returns would join Warner Bros. Animation's expanding list of DC Universe Animated Original Movies, which includes the recently released All-Star Superman, the upcoming Green Lantern: Emerald Knights and Batman: Year One, and the just-announced Justice League: Doom. The latter direct-to-video film will debut early next year, which means we wouldn't see The Dark Knight Returns any earlier than mid- to late 2012.

Set a decade after an aging Bruce Wayne quit crimefighting in the wake of Jason Todd's death, the four-issue miniseries brings Batman out of retirement to save Gotham from sinking deeper into decay and lawlessness. With the help of a new, female Robin, Carrie Kelly, the Dark Knight ends the threat of the mutant gangs that have overrun the city and confronts two of his greatest enemies. But then he must face his former ally Superman in a battle that only one will survive.

Everyone from Watchmen and Man of Steel director Zack Snyder to the Hughes Brothers to Batman franchise producer Michael Uslan have expressed a desire to adapt the influential comic as a live-action film, but the project has never gotten anywhere.