Robbie goes out for a cigarette. I tell Brandon I'm surprised Robbie brought him along after what he'd said about not wanting to hear any debunking.

"There's two sides to Rob in that respect, though, aren't there?" Brandon says. "There's the side that wants to go along with it, but there's also a very sarcastic, sceptical side." He pauses. "Which I'd like to think is the real side." Robbie comes back.

"My toes curled up the moment you walked towards the stage," he tells Brandon. "But I think questioning somebody's sanity when this is happening to them is perfectly acceptable. I question my own."

We're standing near the table where Ann is signing copies of her various books about Jason.

"She reminds me of my mother," Robbie says, glancing at her. "Mum was a tarot card reader. She'd have people round and read their palms. She'd talk about spirits and ghosts. On the shelf of books just outside her room, there'd be the books about the world's mysteries, elves, demons, witchcraft. I was so scared. I'd never talk to her about it. Instead, I just lived in fear of all of this stuff. Maybe that's why I want to investigate UFOs and ghosts and everything. So I can work out why I get scared at night." He pauses. "I'll go and say hello to her."

He approaches the table. "Hi, darling," he says, "I'm Rob. Can I buy a book from you? Will you sign it for me? How is Jason these days? Is he happy? Has he got many friends?"

"No," Ann says, "Jason doesn't have many friends at all. In fact, it's been awful, really. He's socially shunned."

"When did this social shunning begin?" Robbie asks. "What age?"

"I suppose it was when my first book about him came out," Ann replies, "when he was 14. He lost all his friends at school. Nobody wanted to know him. And, of course, word got around the small village where we live. It got very nasty."

"I can completely relate to that," Robbie says. "What is it he encounters from people?"

"In England, in particular, people are really spiteful," Ann says. "They ridicule him. They call out things from across the road like, 'Oi! Mental boy!' "

Robbie puts his hand on Ann's hand.

"Even if this was all made up, which I don't believe, by the way. Even if it was," Robbie says, "compassion should be shown anyway. Well, thank you." Robbie pays for the book and goes to leave.

"You know," says Ann, "you look very much like Robbie Williams." There's a silence. It's as if Robbie was having so much fun, he briefly forgot who he is.

"I am Robbie Williams," he says.

"Can I just say I'm a big fan of yours?" she says.

"Oh, bless you. Thanks, darling," he says. "And please send Jason my best. Maybe we can have a chat one day. In fact..." Robbie writes out his email address for Ann. "Tell him to drop me a line if he wants. It must have been a terrible time for you, and an awful time for him. It's just so sad to hear it happens. It's happened to me."

"Really?" Ann says.

"I think joining Take That was like leaving on a spaceship," Robbie says, "and coming back and all your friends going, 'He's weird now.'"

We queue for the lunch buffet at the restaurant.

"I'm glad I had a chance to sit down with her and talk to her, so I could see her eyes and read her," Robbie says. "She's a really beautiful woman."

"It's interesting that you identified with Jason," I say.

"But that's not what I want to talk about," Robbie says. "Because it's long-winded, and whingeing, and nobody wants to hear a whinger." He pauses. "But if I was doing your job I'd be asking that, because I'm asking the same question of myself, about why that nearly moved me to tears."

He signs a few autographs, and then a few more, and then everyone starts asking for his autograph, including one elderly American who says, "I don't know who you are but my daughter works for MTV and so she might." Word has obviously got around the conference that, in the absence of any aliens, the most interesting thing to have come down from the sky today is Robbie Williams. One conference organiser asks him if he'll consider being their official spokesperson.

"We need someone like you to spread the word and get the young people in," he says. Robbie seems quite attracted by the offer.

"This is possibly the most important thing ever to happen to the planet," he says. "It just amazes me that people aren't as interested as I am in this stuff."

There is so much commotion, we miss much of the next presentation and consequently never find out "what happened when four artists embarked in 1976 on what was expected to be a routine fishing trip".

This isn't the first time that Robbie's fame has hindered his forays into the paranormal world. A few years ago he invited the TV psychic Derek Acorah to his home for a psychic reading. A story subsequently appeared in the Sun under the headline, I Helped Robbie Williams Talk To His Dead Gran:

"Robbie invited me to his apartment in London. We chatted and he told me how much he loved the programme [Living TV's Most Haunted]. He said he had given Most Haunted DVDs to lots of friends, including Robert De Niro, Danny DeVito and Billy Crystal, and they were hooked. I was able to contact a couple of his loved ones, including his grandmother, whom he dearly loved. It was very emotional."

"The twat used my dead nan to sell his DVD!" Robbie told me, quite furiously, at the time. "Plus, I've never met Robert De Niro, Danny DeVito and Billy Crystal. I've never even met them!"

Robbie never spoke to Acorah again, but he persevered with psychics for a while. He met one he liked a lot more, but then one night over dinner the man told Robbie that he wasn't only a leading psychic, he was also "one of only eight people outside Japan ever to be awarded a samuraiship". He said if anything were to happen in Japan, he would have to drop his psychic career "and fly over there to protect the emperor". After dinner Robbie did a bit of research and discovered that nobody has been awarded a samuraiship since 1872 and that "samuraiship" isn't even a real word.

"Haven't all those bad experiences with psychics shaken your wider faith in the paranormal?"

"I suppose they have," he says. "I never watch psychic TV shows any more." He shrugs. "And I suppose it might happen with UFOs, too. And then I might be able to get on with my life."

But if that day ever comes, it's not going to be today, for at this moment an intriguing rumour reaches us. Apparently, a woman tells Ayda, a number of conference attendees spotted a battle between two giant reptilian beings in the desert outside the hotel the other night .

"Did anyone take any photographs of the battle?" Ayda asks her.

"No," she says, "but someone collected a tissue sample and gave it to Dr Roger Leir. He might show it to you, if you can find him."