The Kirkwood brothers who played on "Nirvana Unplugged" are members of the Meat Puppets. Curt Kirkwood played guitar and Cris Kirkwood played bass and sang backing vocals when they joined Nirvana for the 1993 MTV Unplugged performance.
Nirvana performed three Meat Puppets songs: "Plateau," "Oh, Me," and "Lake of Fire." All three originally appeared on the Meat Puppets' 1984 album Meat Puppets II. Kurt Cobain admired the band and specifically wanted its members to appear onstage.
The Kirkwood brothers were founding members of the Meat Puppets, an American rock band formed in Phoenix, Arizona, in 1980 with drummer Derrick Bostrom. Their music blended punk with country, psychedelic rock, and later alternative rock. Their best-known hit, "Backwater," came from the 1994 album Too High to Die.
A common mix-up is identifying the musicians as members of Nirvana. They were guest performers, not permanent Nirvana members. The performance was recorded in November 1993 and released as MTV Unplugged in New York in 1994.