He tells the Belfast Telegraph: "We've three American shows left, then we've a three-week break and then we're off to Japan before the British and Irish tour. Sometimes the road is tough. I've had a bronchial spasm for about nine weeks.

"It's when you've got a cough and all the doctors can't figure out why you have it. It's one of those random things, I just cough for no reason, but luckily I've managed to avoid it onstage."

He continues: "It was brought on, I believe, by the dust and gas emissions from when we played this biker festival. They line up their bikes and rev their engines while you play and when you've got 30,000 doing it you can imagine the kind of air you're breathing in. It can't be good for you."