Brandi Carlile and the Avett Brothers earned one of the most coveted spots on TV earlier this week. The artists performed the country classic "Keep on the Sunny Side" on the Late Show With David Letterman on Monday (May 4), only a few weeks before the TV host retires from his decades-long career.

"I’ve wanted to play on Letterman for my entire musical journey, and I’m so excited to get in here just at the last second!" Carlile shares on her website. "Not a bad night either!"

"Keep on the Sunny Side" is a traditional Christian hymn that was written more than 100 years ago, in 1899. The Carter Family recorded it in 1928, and the Whites sang it for the 2000 movie O Brother, Where Art Thou?

Emmylou HarrisAsleep at the WheelRalph Stanley and Mumford and Sons are all slated to appear before the Late Show's final episode airs on May 20.

Carlile's latest album, The Firewatcher's Daughter, was released in March.

“We took SO many different approaches in the studio and the lead-up to it,” Carlile says. “I’d say the biggest shift that resulted in us really rocking had to do with the fact that we didn’t make any demos. To me, rock ‘n’ roll isn’t really a genre but more of recklessness or a risk … The more something gets ironed out and sure of itself, the less it begins to rock somehow.”

Carlile has a busy touring schedule over the next few months, including stops in New York, Ohio and Texas. A list of all of her upcoming shows is available on her website.