The U2 frontman - who has spent the past two months recovering from an operation after injuring his back in an accident while preparing for a world tour - claims he took up his nicotine habit again because he was so bored.

Bono - who played his first gig since the operation two weeks ago in Italy with bandmates The Edge, Adam Clayton and Larry Mullen Jr. - said: "One of the things you can do when you're lying down like that is to write, so I wrote. Lying motionless I also had time to think about the future, because I never think about the past.

"The other thing I did was to eat ice cream and I also started smoking again."

The 'Sweetest Thing' singer had to pull out of the North American leg of his band's tour and a planned appearance at the world-famous Glastonbury festival because of his condition and he is delighted to be back in action. Speaking at a recent Italian concert, he said: "That's in the past now and I'm very much fit for the future.

"This band is like a family. I am the prodigal son. I would like to thank my brothers for their patience."

Bono was advised to give up smoking by doctors in the late 90s following a bad sinus infection, but he was seen smoking again in 2003 before quitting again for a healthier lifestyle.