Talk about slipping under the radar! Two Nashville celebs tied the knot this week and managed to keep not only the wedding, but their entire relationship under wraps until they became husband and wife!

Trailer Choir's Mark Fortney (better known to fans as "Butter") and Emily Robertson from Carter's Chord were married Monday, September 6, in what you might call an undercover ceremony. Country Weekly reports that guests at Nashville's hip music venue 12th and Porter thought they were there for a birthday party for Butter, but the party turned into an exchange of "I do"s.

Carter's Chord were the first to make the big reveal, posting the news on their Twitter page. "So ... Emily surprised everyone and got married tonight to Butter from @TrailerChoir!!" the band announced. "We're SOOO happy for them!!! Long live love!"

Fellow Choir member Vinny Hickerson, aka "Big Vinny," confirmed the news, tweeting: "First Toby Keith, then [Butter] marries an amazing girl that he met on Toby's tour."

"Well y'all, Butter from @trailerchoir married Emily from Carter's Chord tonight," Vinny later posted." I was the ring bearer -- the worlds largest I might add."

Emily also chimed in via Twitter, confirming the news. "It's true ... Me and Butter got hitched tonight ... SURPRISE!! Thanks for all the sweet replies ... I'm deliriously happy!!!!"

The newlyweds were so good at keeping their nuptials hidden, even the bride's mother seemed shocked by the news. "My daughter Emily just married Mark Fortney in a surprise ceremony!" the happy mom tweeted.

No word on how the couple, whose respective groups are both on Toby's Show Dog-Universal label, will be spending their honeymoon. (Although we're guessing they might not be sharing much of that info on their Twitter pages!)

Chances are they both will be back to work soon. Trailer Choir just released their first full CD, 'Tailgate,' over the summer, while the Carter's Chord ladies are working on a new album.