Alice Cooper has blasted Robert Plant for playing "folk music" instead of reforming Led Zeppelin.
The 'Under My Wheels' rocker - who started his career in the 60s and is still touring today - said he can't understand why his fellow rock vocalist says he can't sing his old band's songs anymore and declines reunions with his bandmates.
Alice, 62, said: "I go out on stage and say 'turn it up'. I never get tired of playing my songs.
"They are just standing there. What is so hard? Jimmy Page wants to do it. John Paul Jones wants to do it. And they got [late Zeppelin drummer John Bonham]'s son Jason, who is a killer drummer. All they need is Robert Plant. But what is Robert Plant out there doing? Playing folk music! What is he doing?"
Robert, also 62, has said on numerous occasions he does not want to get his 'Kashmir' band - one of the biggest rock acts of the 70s - back together, and that their 2007show, a benefit concert held in memory of music executive Ahmet Ertegun, was a one-off.
He said: "It's almost as if people can't see that I have other projects.
"I've gone so far somewhere else that I almost can't relate to it - It's a bit of a pain in the p****r to be honest. Who cares?
"There's nothing worse than a bunch of jaded old f**ts, and that's a fact. People who have written their story - they've gotten to the point where nothing moves. I don't deal in that, and I don't deal with anybody who deals in that."
Robert's recent albums have included 'Raising Sand' with bluegrass-country singer Alison Krauss and 'Band Of Joy' with his first ever band, of the same name