Grace & Tony return for May's new Greenroom Sessions video, but it's this month's special guest that's really impressive.

This time around, Grace & Tony linked up with singer-songwriter Sammy Brue, who met the husband-and-wife duo through Instagram, in Utah. You may not recognize the folk musician's name, but you should: He's gained acclaim from Rolling Stone and American Songwriter Magazine, among others ... and he's just 14 years old!

"During our visit, Sammy kind of took us by surprise when he said, 'Hey, wanna write a song?'" Tony says. "We definitely didn't want to pass up the chance to write with this up-and-coming star ..."

The song they came up with is called "Aside for Now," and it's the tune you'll hear them all perform in this month's Greenroom Sessions video. Brue takes the lead on vocals, and Grace & Tony provide the harmonies.

"In typical Sammy Brue fashion, he wanted to write something heavy, so that's what we did," Tony says. "We hammered out this song, "Aside for Now," in about four hours (which Sammy thought was way too long) and were very proud of the finished product."

Press play on the video above to watch their collaboration, and visit The Boot again on June 15 for another Greenroom Sessions installment.