Jemaine Clement and Bret McKenzie of New Zealand folk-comedy act Flight Of The Conchords are good at cracking people up. But the work that goes into accomplishing those giggles and guffaws is no laughing matter.

Clement wistfully tells Billboard.com, "We haven't been having much fun lately -- we've just been stuck inside studios of one kind or another."

In fact, Tony Kiewel, who heads up A&R for the band's label home Sub Pop, estimates that the duo has been punching the clock "seven days a week for over a year."

But at least that effort is paying off: FOTC's Sub Pop debut, an EP called "The Distant Future," entered Billboard's Top Comedy Albums chart in the pole position and started in the No. 2 spot on the Top Heatseekers tally.

Kiewel says the EP was meant to be a "teaser" for a full-length originally due in the fall, but the duo's busy schedule -- which of late has mostly revolved around their eponymous HBO series -- put the album's release on ice until January 2008.

"The HBO series has been quite difficult," says Clement. "We spent five months writing it, mostly ourselves, and we were on a pretty tight deadline. I mean, I've never done anything like this before, so I have nothing to compare it to, but it seemed like an unreasonable amount of time to make 12 episodes of television."

Besides the challenge of turning mostly pre-existing FOTC songs into fleshed-out plots for the series, Clement only half-jokes that much of the filming was "like NASA training. We filmed the pilot last summer and it was over 100 degrees. We did the shoot in an apartment and had to turn off the AC and block the windows with blankets for sound, and we're in a room with over 40 people surrounded by bright lights. Awesome."

Shooting for the other episodes began this past winter, and Clement laughs that this time they started "during the coldest week of the year, and of course we had to be outside a lot -- it was for an episode where we get mugged, so there we are freezing our asses off running down the street."

The full-length album, due in January, will consist of songs from the soundtrack for the HBO series, but Clement says he and McKenzie are adding flourishes to the tracks. "The songs were done in a hurry for the show, so we're going to go in and do some remixing and just work on them a bit."

Kiewel adds that the album, like the EP, will include HBO branding. "HBO has very much been our partner, especially on the creative/marketing side. For instance, they sent out an announcement to their email list for the EP release. It's been great working with them."

When the album is done, Clement and McKenzie would like to go back to "part-time" with the project, but realize it's not likely. "There's a lot of pressure on us to write a second HBO series as quickly as possible -- probably to air next summer," Clement says.

And of course fans are clamoring to see the act live. Kiewel reveals that "tentatively, there will be a full round of touring once the album's out."

But the easy-going Clement admits to being a little baffled to find himself at the center of all this attention. "Sometimes I'm really surprised I ended up being a performer. In a lot of ways, I've got a job that doesn't suit me. I'm not a particularly social person or the life of the party, but somehow it's ended up that way."

Kiewel, however, says the demand that's been building for FOTC has a simple explanation: "They're ridiculously talented. I saw them in 2005 at the Bumbershoot festival and people were already screaming for their favorite songs, singing along to all the lyrics. Everything they do seems to be met with an amazing response."

And for those already familiar with much of the material that appeared in the HBO show, Clement promises that if FOTC commits to a second series, he and McKenzie will write new songs. "We're already thinking about new material."