Harris stars in the title role— the "low-rent super villain" wannabe — in the new series created by "Buffy the Vampire" scribe Joss Whedon and Maurissa Tancharoen. After launching July 15, the web series remained in the #1 slot of iTunes TV Season for five consecutive weeks.

Also appearing in the series are Nathan Fillion as the superhero Captain Hammer and Felicia Day as Penny, the object of Dr. Horrible's affection.

In addition to the "Dr. Horrible" soundtrack, a DVD release of the entire three-episode series is in the works, which will feature audio commentary from the creators and performers.

Music and lyrics for the series are penned by Joss and Jed Whedon, with additional lyrics by Maurissa Tancharoen. Joss Whedon is also responsible for creating the cult-favorite musical episode of "Buffy the Vampire Slayer," entitled "Once More with Feeling."

Songs on the "Dr. Horrible" soundtrack include "My Freeze Ray," "Bad Horse Chorus," "Caring Hands," "Penny's Song," "Brand New Day," "Everyone's a Hero" and "Everything You Ever." Liner notes and complete lyrics are available by visiting the official "Dr. Horrible" website.

The series was produced on a shoestring budget over a period of six days during the writers strike. Three episodes, roughly ten-minutes each, were filmed.

Neil Patrick Harris' Broadway credits include Assassins, Proof and Cabaret as well as the L.A. company of Rent, the Reprise! and New York Philharmonic productions of Sweeney Todd and the London mounting of tick, tick . . . BOOM! Harris is also well known for his television work on "How I Met Your Mother" and "Doogie Howser, M.D."