On Cinco de Mayo earlier this month, during a widely-watched Late Show with David Letterman featuring an interview with President Obama, the Avett Brothers played American country classic “Keep on the Sunny Side” with Brandi Carlile on vocals. The trio accepted the late night host’s invitation to play one on his favorite songs at the end of his program, cheerfully bringing the Americana staple to a modern audience, giving it a simple, yet poppy feel. After the performance, Letterman thanked the musicians and made note that the cover was “lovely, just lovely.”

The classic “Keep on the Sunny Side” has been around since at least the 1920s, and was made famous in 1928 by the Carter Family from Maces Spring, Virginia. It is a lighthearted song with a positive message, and for such reasons has been able to stay in the good graces of the American public for almost ninety years. It seems that the Avetts are not the only brothers to have paid tribute to the classic—renewed interest in the song, along with bluegrass in general, came with the release of the Coen brothers epic O Brother, Where Art Thou? in 2000.

The Avett Brothers, who hail from Concord, North Carolina, seemed to be right at home playing the folksy tune. It aligns not only with their Southern heritage, but with their musical style, made famous by such albums as Emotionalism and I and Love and You that seemed to seep through the performance. Their bluegrass style harkens back to the time when the Carters were making one of America’s first smash country records, decades before Johnny Cash was even a thought. Although the band has not released an album in about two years, they are getting ready to tour alongside Old Crow Medicine Show and John Prine, among others, starting at the end of May. Their first performance will be at Bottlerock Festival in Napa Valley, California, and from there the band will cross the country, hitting every corner from North to South, except sadly skipping Southern California.

Brandi Carlile, on the other hand, recently released her fifth studio album, The Firewatcher’s Daughter, in early March on ATO Records. The album has been a qualified success, having reach number one on both the Billboard Rock Album and Folk Album charts. She is going on tour on May 22nd, starting in the Northeast and heading South, then West, to eventually get to Southern California in mid-September. She will be playing at the KAABOO Music Festival in San Diego on September 18th.

You can get the feel-goods of the American classic as seen on The Late Show below.