Mumford & Sons have spent most of 2011 working on the [article id="1658237"]follow-up to their breakout Sigh No More[/article] album (when they weren't touring the U.S. [article id="1661351"]by rail[/article], of course). Though they've been performing a handful of new songs live, last month they officially unveiled a somber new tune called [article id="1673657"]"Ghosts"[/article] during a stop at a Philadelphia radio station.

But as the year draws to a close, there's still no official release date (or even a title) for the new album, which sort of makes sense, especially since they're still working on it, as the band told MTV News backstage at the KROQ Almost Acoustic Christmas in Los Angeles.

"We're still recording. We don't really like to put any boundaries on it; we'll keep going until it's right," frontman Marcus Mumford said.

"It's definitely a different experience from the first one, as it should be, I think. But it's been challenging in all the right ways.

It's going well.

"I think we just want the songs to be good, and to sound right, and to feel like we've expressed everything we want to as straightforwardly and honestly as we can ... and we're working towards that," he continued.

"We're really enjoying playing the new songs live, and we still feel that our recorded work should be adverts for our live work.

The fact that we call it work is a bit pretentious -- it's not work, it's just playing music with your mates. It's really fun, and it still is. I think we're getting on better than we ever have."

Mumford said that the songs on the new album have been inspired by their whirlwind year, which not only saw them break through in the U.S., but found them going to places they never thought they'd go and meeting the kinds of folks they never thought they'd meet.

"We've been writing as we go, and you can't deny the fact that our circumstances around us will always affect our writing, so we sometimes intentionally put ourselves in circumstances that we want to be inspired by," he explained. "We went to Nashville for a couple weeks in January and did some really cool writing there; we felt really happy with some of the stuff that came out of it. We stayed in this little farmhouse and had some friends who are musicians come play with us. We played a house show, just had a really nice time. And then we write on the road in these hectic places with lots of people around, and I suppose we've always put in ideas that we pick up from conversations with people, and things that we read and things that we listen to and feel."

Of course, there's also good news for fans of Sigh No More: From the sound of things, the follow-up isn't going to stray all that far from that debut. In fact, it's basically the same songs. After all, if it ain't broke, don't fix it.

"If you're asking whether they're different from the first album,"

multi-instrumentalist Ben Lovett laughed, "what we've actually done is taken all the songs from the first album, used all the same chords, some of the same melodies, and just tweaked the lyrics!"