The Opry stage played host to an unexpected guest over the weekend, as 'American Idol' Season 9 runner-up Crystal Bowersox took the stage. But while audience members were surprised by the appearance, no one was more surprised than Crystal herself. The singer was backstage while the Oak Ridge Boys performed with another 'Idol' runner-up, Bo Bice. Vince Gill, who was performing double-duty as a performer and as the evening's host, invited Crystal to perform for the eager crowd.

"We do things out here for an awful lot of different reasons, but one is spontaneity, one is fun," said Vince. "I went to the management and said, 'Why don't we do the Southern-gentlemanly thing and invite her to sing a song on the stage of the Grand Ole Opry?'"

The new Nashville resident was happy to comply. "I'm standing in the circle!" Crystal boasted from stage. The night was a magical one for the rising star, who performed her self-penned tune, 'Mine All Mine,' while accompanying herself on Vince's acoustic guitar. "I can't believe where I am!" she gushed between verses.

The legendary Opry stage will play host to a celebrity-studded cast this weekend, when several of country music's biggest stars assemble for the Opry All-Star Weekend, which will now include one more superstar. Brad Paisley is the latest artist announced to perform for the event, which will be held March 4 and 5. Other artists scheduled to appear include Carrie Underwood, Blake Shelton, Rodney Atkins and the Band Perry.

In addition, longtime Opry member Jeannie Seely will be in the Opry store on Friday, while Terri Clark will head to the shop on Saturday to meet fans and sign autographs. Tickets are still available for both shows and can be purchased here.

Watch 'Farmer's Daughter'

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