Rascal Flatts are nominated for Vocal Group of the Year at the upcoming 2015 ACM Awards, their first nod at the awards show since 2012. To the trio, who continued to sell out tours and earn No. 1 albums and platinum-selling singles, even without any industry recognition, being included in the list of nominees once again is a welcome, if not slightly overdue, validation.

"It really means the absolute world to us," lead singer Gary LeVox told The Boot and other reporters at a recent media event. "It felt so good to be nominated again. Not that we went anywhere. We've been hopping like we have every year. But you miss what you don't have.

"We were just so humbled and honored. We were just filled with joy," he adds. "I think once you start being nominated a bunch, and you start winning them all the time, it's real easy to get used to it. It just goes to show that you miss what you don't have. We are truly honored and humbled and on cloud nine."

The Flatts, which also includes Jay DeMarcus and Joe Don Rooney, admit that they had stopped even hoping to hear their names included in the list of nominees.

"A few years ago, I stopped waking up and looking at the nominations, because it had just become so normal for us to not be in there anymore," DeMarcus continues. "It was a great way to wake up. It was a fantastic way to start the day, to have so many great e-mails and phone calls from friends, from people that were pulling for us to be back in there. I was really speechless.

"Some might think, if you win it, you've won it, and that's past you," he says, "but when you're trying to still stay viable and stay in the game, it's very, very important and very, very humbling to have those things."

Rascal Flatts will also perform during the ACM Awards broadcast with Christina Aguilera, singing both their current single, "Riot," and Aguilera's current single, "Shotgun," which was written for her role on ABC's Nashville. For the threesome, it's a chance to recover from their flub during last year's ceremony, when they were caught lip syncing during their performance of "Rewind" because LeVox had lost his voice shortly before the ceremony.

"It's the only time we've ever tried it," DeMarcus tells USA Today, adding that they now have "a chance to redeem ourselves, to show everybody we have a wonderfully gifted singer in Gary and a wonderful partnership with Christina."

Performing with the powerhouse vocalist has been a dream of Rascal Flatts for a long time.

"When you make a list of people you want to collaborate with, over the years, that list gets shorter," DeMarcus notes. "Christina was one of those names that's always been at the top of the list, but we'd never had the chance to work with her."

Rascal Flatts haven't won Vocal Group of the Year since 2008, when they took home both the ACM and CMA trophies in the category. This year, they share the category with Lady Antebellum, Little Big Town, the Band Perry and the Zac Brown Band.

The 2015 ACM Awards will air live from AT&T Stadium in Arlington, Texas, on April 19 at 8PM ET on CBS.

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