They thought Lady Gaga was a shoo-in, so when Gloriana heard their name announced as the winners of the American Music Awards' T-Mobile Breakthrough Artist award, the foursome couldn't mask their shock.

"Can we get a show of hands from everybody who just said, 'Who the heck is Gloriana?'" Tom Gossin joked upon accepting the award, as the audience erupted in laughter.

"Hands down, we thought Lady Gaga was gonna win," Rachel Reinert told reporters backstage. "We just freaked out when they called our name."

Gloriana also acknowledged five-time AMA winner Taylor Swift during their acceptance speech, thanking her for having them as an opening act on her Fearless tour this year. Taylor, who wasn't at the show, was the first person to call her buddies to congratulate them.

"I always believed in you guys and always knew you could do it," Taylor reportedly said to Gloriana, adding with a laugh, "But didn't actually think you'd do it!"

Gloriana, who also stake claim to the best-selling debut country album of 2009, will join Taylor again next year on her Fearless tour.