Local hero Win Butler, aka Arcade Fire's frontman, made a surprise appearance in the middle of the band's indie hit song "Seasons (Waiting on You)."

Perhaps unsurprisingly, Butler nailed Herring's raspy register in the track. Butler's appearance also gave Herring the chance to better show off his famed Letterman moves before the pair joined in on the chorus.

The whole duet makes you wonder how and when the started talking. Presumably the pair became friends before Arcade Fire asked Future Islands to open for them at a show in Hyde Park, London, this past July.