'Is there any room in the van?' We are sitting, Shane and I, in the back of a van at the RDS in Dublin, where Paul Simon is due to give his last-ever Irish concert as part of his 'Homeward Bound' farewell tour, when a small, sprightly chap in a baseball cap leaps in. It is a split second before I realise that it is Paul Simon himself.
"Would you like a drink?" he says. We tell him that we would love a glass of wine. He hops out of the van, disappears for a moment and reappears with a bottle and two glasses, one for each of us, and after pouring it, opens a bottle of water for himself. "I can't drink," he says. "But you can."
This is not the norm for legendary rock stars, moments before they are due to go on stage. Most of them need time to themselves, time to prepare. They don't want to chat before a show, especially not an important one. And if they have guests, there are minions to fetch them drinks and to keep them out of the way. Being on a guest list by no means guarantees that you will get to meet the performers.
Shane and I have had the good fortune to meet most rock music legends... Bob Dylan, Leonard Cohen, David Bowie, Eric Clapton, Lou Reed, Paul McCartney, Elton John, Mick Jagger, Keith Richards and so on.
They have all been thrilling and brilliant in their own ways. But Paul Simon is no ordinary living legend. He is that unimaginable creature, an absolute genius, a supremely gifted writer, musician and performer and a thoroughly considerate, compassionate and humble human being. One who will run around trying to find the right drinks for you 10 minutes before he goes on stage.
After a few minutes, James Taylor joins us in the van, and he and Paul compare fingernails. They both have very long, very beautiful nails for playing guitar, and they use various methods to keep them strong. I ask if they have tried gel polish. "Oh gel is useless," Paul says. "It just snaps."
We had not expected to become friends with Paul Simon. It happened quite out of the blue, a few years ago. We got a call from Mick Devine who provides classy cars for all the visiting VIPs. "Paul Simon wants to go to your house," he said.
It transpired that Paul, having heard that Mick knew where we lived, had tracked us down and wanted to meet us. If you had said Beyonce wants to visit, you couldn't have caused more of a fluster. I rushed around in a mad panic, hoovering and tidying and then I realised that we had run out of loo paper so I dashed out to get some. Just as I got back with one of those giant 16-roll packs, a limo pulled up and Paul Simon got out. "You have been shopping?" he said. "Yes," I said. "I got these for you."
There followed a surreal six hours during which Paul and Shane sang and played music together and Paul told us wild and unrepeatable stories - including all the stuff about him and Art Garfunkel - and we all ate salads from my sister's shop and eventually the limo came back and whisked him away.
The next day, a parcel arrived. He had been concerned that Shane was using a battered old record player and had decided to send us a new sound system. After that, we seemed to have bonded. Later on he told me that for him these kinds of friendships are very rare, but that sometimes he meets a person and just feels right at home with them, as if he has always known them.
And so it was a big deal to go to see him play his last-ever tour.
But I could totally understand when he explained why he was quitting.
He and Art Garfunkel became famous when they were 15. He has never known any other kind of life. And he admits that is kind of weird.
"It was very young to have made a decision that you are going to follow your whole life," he says.
And even though he had to start over as an unknown when he moved to England in 1964, he has been on stage now for more than 60 years.
"Of course if you make that choice, you miss out on other choices," he says.
"But I tried to use the fame to meet other musicians from other cultures and I got to have very cool conversations in the world of music. And I have always been most comfortable around other musicians."
His father was also a professional musician, a band leader like himself.
His feelings about quitting are changing all the time, he says. "Sometimes I think, 'Gee, what will I do?' And then I think I'll do something interesting and I'll travel around the world and look at the planet and do what I am supposed to do as a human being and not worry about whether I've got to make another album, or play an old song again. Not that I really dislike it, but occasionally I will run into a patch on tour where I wonder what I'm doing here. Not on this tour, though."
Evidently not on this tour. I have seen him play several times in recent years and it has always been great, but this time his performance is transcendent.
You can feel an effervescence in the energy, as if he is giving it a million per cent, and there is an unashamed appreciation for the audience response. Almost a sense of longing for the applause to go on, for the relationship to continue.
"You know what? This is a terrible, terrible shot. It's backlit and the background is really bad. We have to move."
Paul Simon, Woody Harrelson and Shane are posing for photographs backstage after the gig. Woody Harrelson is directing the shots. After a change of lighting everyone is happy with the pictures.
"You will have to send them to me," Paul says. "And next time I come over, I won't be working, so we will have more time."
"You can play golf," someone says. There is an explosion of laughter.
Somehow, one senses, Paul Simon may be retiring, but he is never going to play golf.