The Bangles, "Grateful" (2003)
One of Grohl's most unlikely appearances came on the Bangles' 2003 comeback record Doll Revolution, where his background vocals earned him a credit as a member of of the "Bangle Boys Choir." Still, the experience didn't leave too much of an impression: "They were next door in the studio, and we'd always meet in the kitchen," he later explained. "They asked if I would sing backup on a song. I went in, did it and never fucking heard it again."