Dave Grohl paid a seemingly impromptu tribute to Tenacious D during the Foo Fighters show in Denver on August 3.

Between songs, Grohl began playing the riff from “Tribute” on his acoustic guitar:

The song is obviously recognizable for Foo Fighters fans, since frontman Dave Grohl was in the music video for the song.

The crowd at Saturday’s show immediately picked up on Grohl strumming the song before he leaned into the mic to say: “You thought I was going to play a Tenacious D song, didn’t you?”

Grohl went on to joke that he really doesn’t know all of the lyrics.