Florida Georgia Line

Tyler Hubbard and Brian Kelley of Florida Georgia Line surprise fans with an intimate performance at The Sutler Saloon on April 14, 2015 in Nashville, Tennessee.

Rick Diamond/Getty Images for Pepsico

It was an uncharacteristically small celebration for bro-country’s resident partiers. At a private acoustic concert in Nashville on Tuesday (April 14), Florida Georgia Line cemented their partnership with the expanding Mountain Dew brand in front of about 150 thirsty fans. 

“I think Mountain Dew represents a good, fun lifestyle, and that’s what we represent too,” the duo’s Tyler Hubbard told Billboard before hopping on stage. “Our personalities and their personality as a brand, if you will, just mesh.”

Florida Georgia Line Cross 'American Idol' Off the Bucket List: 'It Was a Dream Come True'

During the midday set, Hubbard and bandmate Brian Kelley tore through four of their biggest hits: “Sun Daze,” current single “Sippin’ on Fire,” “Get Your Shine On,” and a Nelly-less version of “Cruise.” Meanwhile, the intimate crowd raised mason jars full of DewShine, a just-released throwback soda inspired by Mountain Dew’s rural Tennessee roots. The drink is a riff on old-timey illegal moonshine and is sold in longneck bottles, but -- unlike most FGL lyrics -- contains no alcohol. (DewShine’s retro vibe was enhanced by the event space, a handsomely refurbished saloon called The Sutler.) After the show, Hubbard and Kelley zipped off to the iconic Grand Ole Opry for an evening of back-to-back performances. 

Florida Georgia Line Scores First No. 1 Album

And they’ll keep cruising: Later this week, FGL heads southwest for the 50th Annual Academy of Country Music Awards in Arlington, Texas. They’re nominated in five categories, including the fan-voted entertainer of the year, and are slated to perform “Sippin’ on Fire" (although not with a Johnny Cash hologram as a local news outlet reported on April Fool's Day). And while they won’t be hosting the show, as they did at the American Country Countdown Awards in December, they predict that it’ll still be a hectic evening.

Billboard Cover: Florida Georgia Line on Being ‘Professional Partiers,’ Haters and Hip-Hop

“It’s a one-time thing, it’s live, your adrenaline’s going -- so it’s not like it’s an off night at all,” Kelley said. “A lot of people will be watching.”

Sunday’s awards ceremony, which airs on CBS at 8 p.m. ET, concludes a long weekend packed with ACM media appearances and a duet with David Lee Murphy at the two-day Party for a Cause festival. Then FGL resumes their massive "Anything" Goes tour, which began in January and runs through October. Hey, anyone know where these guys can get a refreshing caffeinated beverage?