It began with a chance meeting in Newport of all places at a Jerry Lee Lewis convention. He a friend of Lonnie Donegan, a fan of John Lee Hooker and perhaps Ulster's greatest living musician; she, a Hank Williams devotee from Tennessee, and sister of the Killer himself.

But if the pairing of Van Morrision and Linda Gail Lewis is hardly a marriage made in rock n' roll heaven, it is certainly one of 2001s more intriguing musical partnerships.

For five or six years now Van the Man has been arriving for two night stints at Oxford's Apollo. And he has also made a habit of bringing along old friends, who perhaps have known better days.

One year Georgie Fame was playing alongside him and we've been treated to Phil May (ex-Pretty Things), Lonnie Donegan and Chris Farlowe. My own favourite saw him sharing the vocal spotlight with both his daughter Shana and the excellent Irish singer, with a taste for dodgy suits, Brian Kennedy.

But his two nights at the Apollo tomorrow and Saturday will see something more akin to a proper music merger, when he will perform with La Lewis and her backing band the Red Hot Pokers.

With Van, you can never be entirely certain what you are going to get. Unlike, other artists with a new album to plug, he is quite capable of ignoring new material in favour of R&B favourites. The sets are rarely the same two nights running. And then of course there is all important Morrison mood factor, which can swing as wildly as a Dizzy Gillespie jam session.

Take Van's shows last year, for instance. On the first night he seemed genuinely inspired by the affection of the audience, all smiles and inviting requests. The sometimes non-communicative Van confided the setting of songs and brought the full house to its feet by performing Them classics like Here Comes The Night, before returning to sing Dylan's It's All Over Now, Baby Blue.

Night two, he walked into his drinks tray at the beginning of the show and had a face like thunder, with chat kept to a bare minimum. One devoted Van fan I know was so affronted by the great man's lack of enthusiasm, that she says she will be sticking to the albums from now on.

The chances are that in the company of Linda Gail Lewis and her band Van's greatest hits will be strictly rationed. The pair produced an album of country and blues standards on Virgin Records, titled You Win Again, which only included one new Morrison composition.

Linda Gail went to see Morrison play in Cardiff soon after the Jerry Lee convention. "My brother Jerry Lee is such a great performer that you imagine you've heard everything," she said afterwards. "But I stood on the side of the stage and when Van started singing it was incredible. He has such a magic in his voice."

After the show they got together and played some songs. "I didn't realise I was going to be singing with him," she said. "He did a couple of blues songs and I played piano for him. It was just a private room. We'd been talking about one of my brother's songs we both loved called Let's Talk About Us. Van asked if I knew the words so I wrote them down for him and he asked me to sing it with him. Suddenly, I was rehearsing duets with Van Morrison."

Van was so impressed he asked Linda Gail if she was free the following week and booked a studio on his mobile phone there and then. "I didn't imagine much would come of it. My hope was that maybe one song might be good enough to emerge on one of his albums.

"He likes to cut everything live. I'd never done that since I made a duets album with my brother back in 1969. Van's a performer in the studio like my brother is. Those guys aren't just recording, they're giving a performance. I just relaxed and decided to have a good time."