It's one of a very few anime based on a western TV show. Warners Japan announced today that the company will be working with Japanese studio Madhouse (which created Death Note) on an anime version of the show Supernatural.
According to Anime News Network:
The anime will be a 22-episode season that will cover the storyline of the live-action version's first two seasons. The first volume will ship on January 12 with the first two episodes. On February 2, the "Box 1" set will ship with episodes 3 to 12. On April 6, the "Box 2" set will ship with episodes 13 to 22. (There will be a different release schedule for the rental version of the project.)
The anime project will not only remake the best episodes from the live-action version, but also depict original episodes not seen in the live-action version. Those original episodes will include prologues of the Winchester brothers' childhood, anime-only enemies, and episodes featuring secondary characters from the live-action version.
Supernatural creator Eric Kripke is credited as the anime project's creator, and Madhouse co-founder Masao Maruyama is serving as executive producer. Naoya Takayama (Night Head, Liar Game) is supervising the series' scripts, and Takahiro Yoshimatsu (Trigun) is designing the characters.
Though Supernatural is in many ways an all-American magicked bromance of the midwest, it makes a perfect fit for anime audiences. The brooding boys who treasure family above all else, fighting demons who want to break into our dimension from another world - it's a classic horror anime. Adding in those exotic American touches like "God" and "hamburgers" will only make it more fun for Japanese audiences.
Needless to say, I'm freaking ecstatic.