Serious work on Dr. Horrible sequel could start soon

Ever since we first reported in January that Joss Whedon and company were planning a sequel to Dr. Horrible's Sing-Along Blog, we've been awaiting news. And now we have some, courtesy of MTV.com.

First, star Nathan Fillion told the site that the project has a name—which he won't divulge—and that Whedon's already written a couple of songs.

Now, Whedon's brother and co-writer Zack Whedon tells MTV that the sequel will get seriously underway once Joss' just-canceled Fox series Dollhouse wraps for the season.

"They finish up 'Dollhouse' in the winter—at least what they've scheduled to shoot thus far—so hopefully when that's done, we'll all be able to get together more frequently and grind it out," he explained. "There are a couple of songs written. It's very promising. We're all very excited about where it goes."

He also confirmed that the sequel will feature Dr. Horrible (Neil Patrick Harris) and Captain Hammer (Fillion). Duh.

"Yeah, you have to see them in the sequel," he laughed. "We will expand the world a little bit into other areas you have not seen... and it will be hilarious."

The entire Dr. Horrible creative team—Joss, Zack, brother Jed Whedon and Jed's wife, Maurissa Tancharoen—are back for the sequel.

But wait: Will Penny be back? Bad Horse? Moist?