The former Czars frontman John Grant went to Iceland to record last year’s Pale Green Ghosts, a sneakily powerful album about living with HIV. It flew a bit under the radar, though we did post the excellent disco-house track “Black Belt.” But on last night’s episode of the Late Show With David Letterman, Grant served as musical guest, singing the excoriating country-rock lope “GMF” and forcing Letterman’s censors to bleep the word “motherfucker.” Letterman, as you can imagine, enjoyed this. Watch it below.

Pale Green Ghosts is out now on Partisan.