Brian Wilson plans to retire from touring because of stage fright and hallucinations.

The 68-year-old Beach Boys singer feels he may not be able to continue playing live as he is getting old and still suffers from nausea and flashbacks, stemming from a sustained period of drug use in the 60s.

Speaking about his forthcoming concerts in London, scheduled for September, Brian said: "This could be the last time I play here. I'm going to miss it but I'm getting a little bit old for touring.

"I'm always afraid just before I go on stage because I'm not sure how the concert's going to work. As I get older it gets harder for me. But when I'm sitting down at the keyboard and my band is behind me, I can do it.

"What the voices say is still pretty much the same, negative things, 'You're going to die', or, 'You better watch out', life-threatening kinds of things.

"Performing helps, but I'll still have the voices there when I'm on stage. They're always with me."

The 'Surfin' USA' star is determined to enjoy what could be his last shows in London, however, as the city is his favourite place and he s he feels his music is more appreciated there than his native US.

He added to London's Evening Standard newspaper: "London is my favourite city in the whole world. I love the people here. I think the people appreciate the music a lot better than Americans do, they're a lot more sensitive to the music than Americans are."