Maren Morris becomes Stephen Colbert's vocal coach during National Anthem duet on 'Late Show'

Maren Morris' Grammy-winning talent and Stephen Colbert's relentless commitment to the track made them the perfect pair of collaborators on the latest episode of The Late Show. Midway through the interview, Morris and Colbert launched into a duet of “The Star-Spangled Banner,” prompting the singer to share stories about the odd places she often played it growing up, like at amateur wrestling matches when she was in high school .

With centuries more experience under her belt, Morris stepped into the role of vocal coach for Colbert, who admitted, “I know the bass line, I don't know the melody.” Her first piece of advice to the host was to start low. “That's the rule. “If you start too high, you forget that you have to go too high at the end with the 'Rocket red glow,'” he warned. Colbert took the notes to heart and delivered an unexpectedly impressive performance — even Morris looked visibly surprised at points.

“I want to sing this with you at an amateur wrestling match,” Colbert told Morris when they wrapped the song, dreaming up ways they can take their new duo on the road. The musician, understandably, no longer frequents these events. When he did, he was 15 years old and was paid $100 to sing for a minute and a half every weekend. “I had more fun,” he said. “And it was a fun way to make money and be patriotic.”

Morris will hit the road solo later this year on a tour that will work similarly to Colbert's spontaneous request to sing the National Anthem with him. RSVP Redux's upcoming tour, which kicks off at the end of May, will allow fans in each city to choose the setlist to perform at their show.