NEW YORK -- From YouTube stars to pop sensations, Karmin have certainly come a long way from recording cover videos.

This past year, real-life engaged couple Amy Heidemann and Nick Noonan released their debut EP, Hello, and their single "Brokenhearted" became a smash hit. Plus, this month, Heidemann is gracing the flip cover of [article id="1694453"]Rolling Stone's first-ever "Women Who Rock" issue[/article], as voted by the mag's readers.

"We are so grateful and we feel really blessed, and we can't wait to see what next year brings," Heidemann told MTV News at the Hard Rock Cafe, where they performed as part of Rolling Stone's private concert series. "There's a lot of cool stuff in the works."

It seems their fans, a.k.a. "Karminites," will see some of that "cool stuff" very soon, since Karmin, who admitted that even though they haven't started [article id="1691420"]planning their upcoming wedding[/article], are deep into their debut LP.

"We've started working on a new album, and that's, like, the most exciting thing for an artist," Heidemann said. "We'll be cooped up in the studio."

"I think the entire month of November, we just cleared that entire thing," Noonan added. "We're just gonna go in and try to make some magic."

And it seems like they have a host of material to bring into the studio, since they've already begun writing. "We're living on airplanes, so while we are there, we figured we might as well try," Noonan said of songwriting. "So I'm on the laptop and recording things, so we have some ideas."

"We look really strange on airplanes, because people are like, 'Are those people dancing over there? And she's scribbling something?' " Heidemann laughed. "It's weird."

Karmin, who plan to release the album at the top of 2013, are hoping to evolve their sound on their next effort, revealing that they are going to incorporate more live instruments and give Noonan more of a chance to show off his vocal skills.

"One thing that the fans wanted and that I really am excited about is having more of Nick singing," Heidemann said. "It felt very Amy-heavy on our last release, so more of Nick."

And even though these two are always working together, they are open to collaborations and already have someone in mind to make a guest spot on their upcoming album.

"There's one song that we just wrote that Amy would love to hear Shaggy on," Noonan said of the "It Wasn't Me" reggae singer. "He's Shaggy; he's amazing."