Springfield may be a world away from Watford but The Simpsons and Spinal Tap star Harry Shearer is gracing us with his presence for a very special gig at the Palace Theatre - Barry From Watford's Royal Variety Show. Harry and his wife Judith Owen will be performing some rock-out comedy numbers. Judith, originally from Wales, is a singer songwriter in her own right and regularly teams up with Rickmansworth musicians Danny Thompson and Laurence Cottle. Laurence plays electric bass on her latest album Some Kind of Comfort.

The stellar line-up also includes stand up comedian Lee Hurst (They Think It’s All Over) and close harmony group The Segue Sisters, plus a mystery comic to be revealed on the night.

Barry, played by Oxhey actor Alex Lowe ('dad on train' in the latest NatWest advert), has been playing away from home to packed out audiences at London's 100 Club on Oxford Street with his monthly Barry's Bingo Bonanza nights - a hilarious mix of seemingly random comedy acts, up and coming bands and one-off 'turns'. Now he's bringing the mirth home and Harry, who went down a storm at the 100 Club earlier this year, is top of the bill.

So how did this particular odd couple get together?

"We met on a doomed Radio 4 comedy show about six years ago called Not Today Thank You," recalls Harry. "I'd started my career on Jack Benny's radio show which was in front of a live audience and I thought it would be fun to revisit that.

"Alex was among the incredibly talented people in the cast.

"I saw Barry's show at the Fringe a couple of years ago. He's a great comic character and he has this old-fashioned sense of humour. He generally draws an audience who have a tendency to consume an early-bird supper and like their entertainment to be loud but young people at the 100 Club are also digging his retro groove."

A child actor, Harry appeared in the 1953 film Abbott and Costello Go to Mars and The Robe. What kept him grounded in those early years?

"What made it easier is that my parents were really, really sane and that makes all the difference when you're in showbiz. Any show where they thought I was not being treated well, I wouldn’t do again. They knew I loved it - as a kid there was no place I'd rather be than on set hanging out with the grown-ups. I don’t think any of us thought it was what I'd end up doing, for me it wasn't about fame, money, building a career or any of that stuff. I just stumbled on the place where I could have the best time and the most fun."

Harry has been giving the fun back in spades. The seminal 1984 mocumentary This Is Spinal Tap about an ageing metal band, quickly achieved cult status and launched an enduring partnership between Harry and co-star Christopher Guest.

For their final 25th anniversary tour in 2009, Harry popped over to Thwaites in Watford to hire some equipment for the band's Wembley Arena gig.

I ask Harry what he thinks the enduring appeal of Tap is and why have they never done a sequel?

"People liked it because it was so damn loud. There was a wonderful time after all the motion picture houses in Hollywood who thought we were crazy and had said no to us, ten years later were proffering ridiculous amounts of money and we got to say 'no' to them. We've said it about as well as we can and I personally think if we were to do something like that we'd have to endure all our fans coming up to us with that sad look in their eyes."

Actor, author, director, satirist, musician, radio host, playwright, artist and record label owner, Harry is of course best known for his voice work for The Simpsons and The Simpsons Movie playing a stable of characters including Mr Burns, Smithers, Ned Flanders, Principal Skinner and Scratchy from 1989 to this day. Did he ever imagine the show would last so long and achieve such success?

"No. And anybody who says 'yes' is lying. We started out on a seldom used and watched UHF TV network where very often people's normal roof antennae didn’t receive the signal very and they'd have to improvise with wire coat hangers - that's how marginal it was. We couldn't have imagined a major network would pick it up four years later, let alone that our show would have been on air for more than 20 years."

How long does he see The Simpsons going on? Could you go on forever?

"Forever is a long time. I couldn't do another 25 years for health reasons. I suspect the 25th season will be the last and in a sense maybe that will be an unmatchable record - I don’t know and they don’t confide in me. "I've never been involved in the development of the characters only as to how they might sound and in most cases they've continued to sound that way. There's almost no improvisation in The Simpsons beyond the character's way of speaking - it's an acting gig. I do what other people write."

I ask Alex if he thinks Barry has legs and will keep putting Watford on the map?

"Yes, Barry will go on forever.....or until people get bored of the old git."

Barry From Watford's Royal Variety Show is at Watford Palace Theatre, Clarendon Road, Watford on July 20 at 7pm. Details: 01923 225671