Brian Wilson is talking, as best he can, about the voices he hears in his head. They are not there every day. Sometimes he even goes a few weeks without hearing them. But when they do come, they terrify the life out of him.
"I hear them saying, 'You're OK, you're OK, you're OK.' Then I'll suddenly hear..." - he puts his hands over his ears and shouts - "'You're gonna go, you're gonna get it, you're gonna get it.' And I say, 'Oh my God, what's going on?' I feel real scared. I don't know where it's coming from. I think it's mostly a hallucination, but I think some of it is real. It certainly feels real."
Not for the first time, I wonder if we should go on with our conversation, and whether Wilson is really up to the task of discussing the harrowing details of his existence with a stranger. It's well known that the years of drug addiction and debilitating mental illness have taken their toll on him. But in all the interviews I've done, I've never met anyone so bewildered, so fragile, so clearly close to the edge. Even the simplest things seem to elude him. Over the course of an hour, he asks me my name four times - in one instance he gets me to spell it - but he calls me Winona anyway. It seems easier not to argue.
We meet in the presidential suite of a hotel in Universal City, just across the valley from Wilson's home in the Hollywood hills. Physically, he's much bigger than you'd expect. I had always imagined him to be shrunken and crushed-looking, but he towers over everyone in the room. His upper body is an almost perfect egg shape, with sloping shoulders leading down to a broad, protruding belly. He's dressed all in black, accentuating his pasty grey complexion.
For our interview he sits stiffly on the edge of his seat, his hands clamped to his knees, talking in short, hesitant bursts. Perhaps because he's at a loss for something to say, he'll often repeat himself. In other instances he'll let his answers trail off, as if backing away from memories too painful to share.
As a singer and composer, and founding member of The Beach Boys, Wilson is responsible for creating some of the sunniest and saddest songs pop music has known. While they were still in their teens, he and his fellow Beach Boys - his brothers Carl and Dennis, his cousin Mike Love and their friend Al Jardine - composed songs that encapsulated the innocence and optimism of Sixties California, such as "Surfin' USA", "Barbara Ann" and "I Get Around". But the shy, introverted Brian was to buckle under the weight of his own genius. By the time he was 30, this once handsome youth had become a 25-stone recluse who, legend has it, only left his bed to check the mailbox where he would receive his daily fix of cocaine.
During the Eighties, Wilson fell under the spell of Eugene Landy, the Rasputin-like psychiatrist who had been hired by his wife Marilyn. Landy managed to get him out of his bed, off drugs and on a diet, although his influence on other aspects of Wilson's life began to alarm those around them. When, in 1990, Landy allegedly persuaded Wilson to re-draft his will, a lawsuit was filed and all contact between the two men was severed.
Wilson's brothers are now dead: Dennis drowned in 1983, while Carl died of cancer seven years ago. It's a strange irony that Brian, whom no one expected to see out his twenties, is now performing and making music again. For the last two years he and his band The Wondermints have travelled around Europe and the United States performing his endlessly worshipped album Pet Sounds and its unreleased follow-up Smile, to ecstatic critical reception. Next week, Wilson is set to release a new solo LP, the ominously titled Gettin In Over My Head, which features collaborations with Elton John, Paul McCartney and Eric Clapton. It is, at best, a patchy piece of work that desperately tries to evoke the bittersweet wistfulness of his Sixties heyday.
Right now, Wilson's worried that no one will buy it. "I don't think the new generation is on to my music at all," he says darkly. "I don't think they like it. There are some young people that like my music, but there are a lot that don't. They just like rap music - I call it crap music. He-he-he."
Given Wilson's brittle state of mind, it's impossible to imagine how he functions as a touring musician. He admits to being regularly crippled by stage fright. "For about half hour before I go on stage I'm almost throwing up," he says. "I'm so scared, it's really unbelievable. I didn't have it with The Beach Boys, I've only had stage fright with my solo career." Does he know why? "I really don't know," he says. When I suggest that maybe it's because the focus is on him, he nods vigorously, thankful I've given him something to say. "Yeah, it's because the focus is on me and it puts me under more pressure, which makes me feel afraid."
Wilson talks a lot about being afraid - of the voices, of failure, of never being able to write another song. The first time he remembers feeling fear was in the presence of Murry, his violent and domineering father, who took his own failure as a songwriter out on his sons. Despite this abuse, Wilson maintains that the band wouldn't have got where they did without him.
"He was the fire under our butts," he says, smiling suddenly. "He was the one who got us going. He didn't make us better artists or musicians, but he gave us ambition. I'm pleased he pushed us, because it was such a relief to know there was someone as strong as my dad to keep things going. He used to spank us, and it hurt too, but I loved him because he was a great musician."
In 1964, Wilson suffered the first of a series of breakdowns. He was on a flight to a show in Houston when he was found wailing and crawling on his hands and knees in the aisles. After that, he stopped performing live and retreated to the relative security of the recording studio, leaving Dennis, Carl and Mike to keep up the band's public profile on tour.
In 1966, he wrote what is considered to be his greatest album, Pet Sounds, which included the spookily prescient "I Just Wasn't Made for These Times" and the elegiac love song "God Only Knows". Conceived partly as a response to Rubber Soul, the album prompted The Beatles to create their own concept album, Sgt Pepper's Lonely Hearts Club Band.
"They say Sgt Pepper and Pet Sounds were the two greatest albums ever made," reflects Wilson blankly. "I'm very proud to think that we could have made an album that good. It was easier back then because I was young and had energy. I wanted to make love music. I was in the mood for love music." But the album was rejected by the rest of the band. Mike Love wrote it off as "Brian's ego music". That must have hurt, I say. "Yeah, but I knew they wouldn't like it. In the end I made them like it. I said, 'You guys like this, you love it.' And they said, 'Yeah we do.'"
Wilson tries to play down the feelings of rivalry with The Beatles that sent him into a psychological tailspin when he was writing Smile. "I never felt any competition," he maintains. "I felt a friendly rivalry. I didn't feel, 'Hey, I can do better than The Beatles.' It wasn't that kind of thing at all. It was just a natural rivalry."
Wilson's neurosis during the making of Smile has passed into rock mythology. He had his grand piano placed in a specially-built sandpit in his living room so he could feel the beach beneath his feet. This, along with an incident at his studio where he set a fire in a bucket so the musicians could draw inspiration from the smoke, was seen by his friends and family as proof of his spiralling madness. Eventually, Wilson pulled the plug and Smile was canned.
I ask how he felt at the time, and Wilson replies quietly: "Unstable, unhappy. I was thinking, 'Oh my God, what am I going to do next? What's this next thing going to be like?' I was feeling this pressure, all this pressure to do something great, and it made my mind hurt."
That Smile, the album that drove Wilson over the edge, is finally reaching the record shops this autumn, 37 years after he started making it, makes you concerned for his sanity. He says that he's happy with the work he and the original producer Van Dyke Parks have done on it over the past year, but adds that he's nervous about releasing it. "I'm nervous that it won't sell, that people won't like it, that they will be disappointed." Is other people's approval still important to him, then? "Yes. I'm not confident at all. Not at all."
You wonder where Wilson's career would be now were it not for the people around him driving it forward. He says it was his second wife Melinda's idea to tour Pet Sounds and his manager's idea to tour and release Smile. Left to his own devices, perhaps he would be happier tinkering in his studio alone, safe in the knowledge that his songs would never be heard and therefore never judged.
On the other hand, Wilson says he is never happier than when he is singing on stage and making music. He describes the moment when a song forms in his head as "an inspiration from God. It feels Godly. It makes me happy." Does he feel happy now? "Sure, I'm happy" he says, forcing a smile. "Not right this moment," I say. "Are you happy with your life now?"
"Not as happy as I used to be. Ten, 20 years ago I was a little happier. I think because I'm getting a little older, it makes me feel depressed. I've been afraid of death lately. I've had fears of dying. Not that I'm not going to die right now. Not today. But within 20 years I'll die, and 20 years is like that..." - he clicks his fingers. "That's real scary."
Wilson's new family has done much to heal the scars of his past. He and Melinda live with two adopted daughters Daria, seven, and Delanie, six (he has grown-up daughters from his first marriage). His music commitments only account for about a third of his time; the rest he spends with his children walking in the park, eating at local restaurants, going to baseball games or just sitting at home in the garden. He also sees a therapist every week.
He looks back on his years as a Beach Boy with a mixture of pride and regret. "I like the music, but I regret things. Drugs have destroyed some of my abilities. LSD really messed my head up. But [drugs] have helped me out when I've needed them. Medicine for depression and medicine for anxiety have helped me out a lot. It could be a lot worse."
With that, the interview seems to be over. Wilson gets up and wanders off to the bathroom. When he comes back, he addresses me as Winona again and asks for a hug. "I enjoyed that," he says as he pulls me into his enormous belly: "It was fun." His sudden warmth is touching, though it strikes me that life is far from fun for the man hailed as pop's greatest living genius. I wonder to myself if he will ever find real peace and contentment. Can Brian Wilson ever live up to the legend? God only knows.
'Gettin In Over My Head' is out now on Eastwest/Rhino. Wilson begins a UK tour at the Eden Project, Cornwall, on 16 July. He performs 'Smile' at the Royal Festival Hall, London SE1 (0870 401 8181; www.rfh.org.uk) on 24, 25, 27, 28, 30 and 31 July. 'Smile' is out on 27 September