Any of you Nashville troubadours who were left wondering what Robert Plant was doing hanging around earlier this year now have an answer.

It comes in the form of Plant's duet album with country singer Alison Krauss, Raising Sand, due out October 23.

This follows the trend set recently by Bon Jovi and John Mellencamp, who have both actively pursued the country music market. But, you may remember that the two dueted at the Rock and Roll Hall of Fame tribute concert for Leadbelly a few years ago.

T-Bone Burnett, a Gillian Welch mainstay and the most of the brains behind the soundtrack for O Brother, Where Art Thou?, produced the album for the couple. It features covers of songs by Mel Tillis, Tom Waits, Townes Van Zandt, Gene Clark, Doc Watson, Milton Campbell and the Everly Brothers.

The album also features contributions from Marc Ribot (who often plays with Tom Waits), as well as Mike Seeger and Norman Blake.