Robert Plant has owned up to teasing Alison Krauss by playing around with his vocals while they perform live. They’re currently on tour in support of second album Raise the Roof, which again finds the duo reinterpreting material by blues, folk and Americana artists of the past.

Krauss earlier said the pair work well together because her “regimented” approach was a contrast to his “freedom and spontaneity.” Plant confirms that in a new interview with Rolling Stone: “I’m still slightly impish, so I might hold one syllable of a word a little bit long, and she hangs on with me, and she doesn’t know when it’s going to end, that particular syllable.”

He said their “eyebrows tell everything” when he pulls his trick. "She’s asking me, ‘Why am I doing this? Why are you fucking about like this?’" he explained. "It’s great. … I have this license where I can actually get away with it, and I’m singing alongside a monster singer who has great demands of how my harmony fits under the songs that she selected.”

Plant reflected that his present-day performances contrasted with the “panic of responsibility” he felt with Led Zeppelin in the ‘70s. “There was nowhere to hide at all," he said. "There were great days and there were days that weren’t so good, and I would have to push through. A lot of what I was singing was really at the top of my capacity, right at the sharp end of what I could ever possibly do.”

Things changed after Zeppelin ended, he added. “From then on, I made a lot of departures, and I have no embarrassment about them," he said. "They were all rather silly adventures, but they kept me thinking, or just falling upon melody.” Despite his age, Plant asserted, “I can still do all the shit that I could do before, because occasionally through these shows I let it rip for a minute, and I know very well that that’s as much as we need to do of that.”

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