The hearts of fans at Sharon Van Etten's First Avenue show were already good and tender by the time the singer-songwriter got to her encore. The Brooklyn-based singer-songwriter had already delivered over a dozen smoldering songs, including many from her new album, Are We There, and returned to the stage solo to present a mesmerizing solo rendition of the Lou Reed song "Perfect Day." But few were expecting the surprise twist to the end of Van Etten's set: a cameo from her Jagjaguwar labelmate Justin Vernon, who crept up on stage to accompany the band on their final two songs.

The cameo was Vernon's first appearance in the Twin Cities since he played with the Shouting Matches on the same stage almost exactly a year ago, and the thrill of seeing the regional hero in person was immediate, and loud. There was screaming. There was crying. And there was at least one dude exclaiming, "Wow wow wee wow wow!"

The pair duetted on the heartbreaking early Van Etten song "Love More" with Vernon hovering over a keyboard and crooning the harmonies in his signature high-register falsetto. Afterwards, Vernon lingered on stage and picked up an electric guitar for the set closer "Every Time the Sun Comes Up," which is the final track on Van Etten's new album. The chemistry between the two performers was obvious, and Vernon took time to hug the singer (and her bass player, Brad Cook, who was Vernon's bandmate in DeYarmond Edison and the Shouting Matches) before shyly waving to the crowd and ducking off stage.

After playing "Love More," which rarely makes an appearance in her live shows, Van Etten explained that it was the song that first brought Vernon into her life. After the show, Vernon expanded on that story, telling me that he initially admired Van Etten's music from afar and that he covered "Love More" for the first time back in 2010 when he was invited to play Cincinatti's MusicNOW festival. A year later the pair duetted on a song at the same festival, and in the time since their friendship has blossomed and their respect for one another has only grown.

For more on Sharon Van Etten's new album, tune in for an in-studio she recorded with the Morning Show's Jill Riley tomorrow morning, Friday, July 17, at 7:30 a.m.