Ask the 4,000 or so residents of Hailey, in the Sawtooth Mountains of deepest Idaho. Eleven years ago, Bruce bought a ranch there in an attempt to escape from Hollywood. Now he and his wife own half the high street - including a cinema, bistro and potential doll museum - and the good citizens of Hailey cannot escape the fact that Hollywood has come to them. It is not so much a case of My Private Idaho as My Privatised Idaho.
Could Berkshire be next? "Oh, that simply is not true," said the newsdesk at the Idaho Statesman in the state capital, Boise. "They are just doing some real estate deals in Hailey. We are covering this on the real estate pages." Yet nobody could take any comfort in the statement from the couple's spokesman: "Mr Willis is not packing his suitcases and leaving town. This is the liquidation of idle assets as we focus our operations to enhance profitability."
That, as they say in America, sounds like a go situation. When did the star of Die Hard need to pack a suitcase, anyway? Those T-shirts can easily be handled as carry-on (though there might be some trouble with the automatic assault weapons). Any striptease artist - as Demi Moore should know, since she recently played one - is an expert at travelling light, though daughters Rumer, Scout and Tallulah would come along too.
The flight might be rather crowded. Both Madonna and Sylvester Stallone are thinking that England might be just the place to raise children. "People read here," says the Material Girl. The thought of Rambo at at the local cricket match is almost as odd as Michael Jackson in a kilt. The Gloved One is scouting Scotland for a castle suitable for bringing up baby, not to mention the chimp and the Ferris wheel.
Since November, Nicole Kidman and Tom Cruise have been renting a 20-bedroom Hertfordshire mansion, set in 50 acres near Shenley. "The family arrived with the requisite Hollywood entourage of two bodyguards, personal assistants, his-and-her personal trainers, a French chef and two nannies," reports OK! magazine. The couple keep a Gulfstream jet parked at Luton for weekend trips home, and a Beach Baron at Elstree aerodrome.
Bruce and Demi already have houses in Malibu and Manhattan, and they are as much jet-ski as jet set. A friend says they are seeking something in the pounds 3m range because they are impressed by Britain's "peace and safety" and its drug- and violence-free schools. This is a different Britain to the one most of us know, but it rings true when compared with much of America. However Hailey is not most of America, and one suspects that the power couple is looking to buy a house here but not a home.
There really is no comparison between rural Berkshire and wildest Idaho. Rolling hills are all very well, but the gold rush town of Hailey lies in one of the most beautiful parts of one of the most beautiful states in the Union. The Idaho mountains take your breath away - and they are high enough to - and there are bubbling hot springs, crystalline lakes and babbling brooks ad infinitum.
The blot on this landscape is a human one: the Potato State is the kind of place where Mormons just cannot seem to knock on your door often enough and where everyone seems to be Republican and assumes that you are, too. It is a weird mix of the old west - wild horses do still roam here - and white supremacist.
But Hailey and the neighbouring ski resort of Sun Valley have escaped this human factor. "This is a liberal island in a conservative sea and that makes it even cooler than its average temperature allows for," says Wayne Adair of Hailey. The lifestyles of the rich and famous have fostered prosperity. There is an excellent school system, the air is clean and the water is very high quality, There's not much crime. Most people don't bother to lock their cars, and some don't lock their houses at night, either. "It's a real friendly place," says Adair.
So far, so very far from California. But Demi and Bruce have made an impact - an $8m one. They have turned an old honky-tonk on Main Street into a 160-seat bistro trimmed in mahogany and chenille-covered sofas. The cinema was a wreck, but is now a vision in burgundy and bronze velvet, gilt and glass. Demi has installed love seats in the balcony. "It's so romantic," she says. Also renovated is the EG Willis building - if you own the building, you get to name it after your grandfather.
"My kids are going to grow up here and I just want to make it a little nicer," Willis told the Wood River Journal. Actually, he wants to make it a lot nicer. On 4 July, Bruce paid for the town's fireworks and rode in the parade. He makes large donations to local charities. He is looking for something he calls "living in the Fifties".
This suddenly makes the idea of Berkshire much more logical. Demi and Bruce could host the summer fete, not to mention the odd bring-and-buy sale. It is difficult to imagine the star of Disclosure joining in the church flower rota, but no doubt the WI could bend to holding competitions involving arrangements of rocket lettuce leaf and pine nut kernel. The Die Hard factor could come in handy with neighbourhood watch, and Berkshire could benefit from a well-placed million or two.
The Moore-Willis combination has boosted the fortunes of Hailey, but one needs look no further than Braselton, the Georgia town that Kim Basinger bought for pounds 14m, to see the dangers. She went bankrupt and the town was destitute. Steve Kearns, mayor of Hailey, offers this perspective: "Sure, you can get nervous about one family having a lot of control. But the things they've done are in keeping with the character of the town. They don't want to make it into Planet Hollywood."
And yet and yet ... on the West Coast of America it is stated as fact that Californians want to take over the world. In reality, many are escaping from the earthquake zone, and the Monterey factor can now be seen across the Pacific North-west: perfect pasta and pinot noir are everywhere. There is even a word for it - Californicate - and the inevitable bumper sticker that says "Don't Californicate over my backyard". Of course, the same people who plaster these all over their cars are happy to accept the many dollars that Californians possess.
This is their secret weapon. And it is worth remembering that on the West Coast, there is a thing called a "California stop". This is when drivers slow down for a stop sign but never actually come to a halt. Instead, they just glide through it. So Berkshire beware: we are dealing with people who do not know when to stopn