Alison Krauss

It was announced on Friday afternoon that Nelson would be taking a few days off per doctor's orders.

Live version of the Led Zeppelin classic is the duo's first official release in two and a half years.

Duo began their trek with a performance in Tulsa, Oklahoma.

The trek begins June 2.

Gov't Mule, the Avett Brothers and many other acts will appear on various dates.

The duo's March performance at Red Rocks will be available as a worldwide stream.

Duo adds 13 stops to itinerary, keeping them on the road through September.

Led Zeppelin legend felt "exposed and vulnerable" as duet album ‘Raising Sand’ began to form.

One of the songs Plant recorded alongside Alison Krauss was "a hell of a challenge."

New LP would be the follow-up to 2007's 'Raising Sand.'