Robert Plant and Alison Krauss

Led Zeppelin frontman Plant paired up with the fiddle-playing star to record a duet for the collaborative album, Raising Sand - and was blown away by Krauss' talent.

Plant says, "We were just sitting back looking at each other, going, 'S**t'. I mean, she taught me to sing!

"I thought I'd probably been around too long but she taught me to sing delicate harmonies."

Source: WENN