MACHINE HEAD frontman ROBB FLYNN is to have his gallbladder removed – just weeks before the band head out on tour.

He expects to go under the knife tomorrow (Tuesday) after doctors advised him the pain caused by a gallstone they'd found would make life on the road unbearable.

He says in a video: "I had food poisoning about a week ago and I've had this pretty severe pain under my right rib since then. I've been to the doctor a few times but they don't know what it is, so the only way I could get in was to go to emergency. I have a gallstone in my gallbladder and I need surgery to remove it. And I'm getting ready to go on tour in two fucking weeks, for seven weeks."

But he believes he has no option. "In 2012 I had hernia for a year and a half, and I put it off because I discovered it at the beginning of a tour cycle," he recalls. "It just got too painful on the road. I can't really take the pain and we need to do the tour."

Flynn adds: "It's not just the gallstone they're removing – they actually have to remove my entire gallbladder, which I guess you don't really need. I had my appendix removed was I was nine or 10, and I haven't needed that."

MACHINE HEAD are scheduled to start their tour on May 25 in Mexico, ahead of a wider run of South American dates. They then head to New Zealand, Australia, Japan and Europe. The Sofia-Bulgaria date is 24 September.

They released latest album Bloodstone And Diamonds last year.