[artist id="3181423"]Fun.[/artist]'s "We Are Young" has become one of the year's most-unlikely sensations, leaping all the way to #3 on the Billboard Hot 100 singles chart -- behind only Kelly Clarkson and Adele -- thanks in no small part to massive digital sales, a plum feature on "Glee" and, of course, that [article id="1676679"]iconic, chaotic music video.[/article]

So now, with a certified hit to their credit, Fun. are gearing up for the next phase of their climb: the release of their second studio album, [article id="1677668"]Some Nights[/article], out Tuesday (February 21). It's a whirling, ambitious listen, the sound of a band busting boundaries and reaching for bigger and better things -- "It's been a long time coming, and we want it to take over the world," frontman Nate Ruess said -- so it's fitting that it's been preceded by "We Are Young," a song that very much busts boundaries, and gets unapologetically big.

"That song, to us, is like bull's-eye center of what we wanted to do with this album," guitarist Jack Antonoff told MTV News. "It's a brilliant song to have out as a single, because it's saying all the things to people that we want to say. It's showing how, artistically, [the album is] different, it's showing all the influences brought by Jeff Bhasker, who produced the album, and all he brings from his hop-hop world, working with people like Kanye and Jay-Z. And it shows where we've moved with songwriting.

"And one of our favorite things about 'We Are Young' is that, if it's the center of the album, every song is sprouting out of it in different directions," he continued. "And if you like the song, then I think the album's just going to be a rollercoaster ride, because it just flies in every direction in and out of that song."

In that regard, "We Are Young" has also become Fun.'s de facto anthem -- by their own admission, their first -- the song that they feel speaks best for this band, at this moment, on the verge of very big things.

"It's pretty rare, because any other projects that we've done, I don't think any of us have ever had that song that was like, 'This is our band,' " Antonoff said. "We're proud to say, 'Listen to this one song, and then come listen to the rest. Here it is.' "

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