Minneapolis' Polica is made up of Channy Leaneagh and Ryan Olson, who used to be in the rotating musical collective Gayngs, which also included Bon Iver's Justin Vernon.

On their new single, 'Tiff,' Polica enlist their old pal for a soulful, electronics-washed slow jam that's as smooth as it is ghostly. It sounds more like Cat Power than Bon Iver, with Leaneagh's velvety vocals floating on top of a gurgling R&B rhythm.

Vernon, who shows up as a backing singer during the choruses, called Polica "the best band I've ever heard." He likes them so much, he even joined them onstage when they performed 'Tiff' at Coachella this past weekend.