It's been a while since we've heard from Bono, but the U2 frontman made a surprise appearance this week at a concert by Glen Hansard of the Swell Season at the Living Room in New York City, joining his fellow countryman onstage to sing the Irish anthem 'The Auld Triangle.'

Hansard's performance was taped for Sirius/XM’s 'The Loft' program. According to a fan account, Hansard performed an hour-long set before kicking off his final number, 'The Auld Triangle.' After practicing a singalong with the audience, Hansard said, "I've got a buddy who's going to sing with me," and out came his superstar guest.

The video shows Bono and Hansard having a good time as they exchange verses and sing with the lucky members of the crowd. Midway through the song, after a particularly energetic chorus that feels like the climax of the song, as Hansard continues playing, Bono says, "There's actually one more verse ... Give me a second. It's kind of a good one, if I can remember it."

Hansard might be best known for his work with Marketa Irglova as the folk duo the Swell Season and the Frames, but the singer is branching out on his own now with the release of 'Rhythm and Repose.' His solo debut on Anti Records hits retailers on June 19. Hansard will launch a short U.S. tour on June 12, when he'll be back in NYC for a show benefiting Housing Works.

Watch Bono and Glen Hansard Sing 'The Auld Triangle'