Most Oscar-winning actresses choose to spend their summer holidays lounging on an exclusive beach, visiting glamorous festivals or sunning themselves on private yachts. But Tilda Swinton has always taken the road less travelled.

And the inspiration for her latest unorthodox venture - hauling a portable cinema from the west coast of Scotland to Nairn with film-maker Mark Cousins, stopping in villages and hamlets along the way to screen movies - comes from a suitably offbeat source.

Speaking exclusively to the Sunday Herald, the actress, who won an Oscar last year for her role in Michael Clayton, said the idea for the wandering cinema came years ago, far from the glens their festival will visit in August.

"I once was present at a screening of an old Western projected onto a sheet on a tree in East Africa to an audience that included Meru tribesmen, one of whom threw a spear into the screen' during the shootout," she said. "It hung there throughout, until the kiss at the end. You could say I have always wanted to take a roving cinema out and about ever since."

A more mundane practicality also prompted Swinton and Cousins to take their cinematic vision to the highways and byways of Scotland. Last summer, the pair put on a quirky alternative movie festival in a disused dancehall in Nairn which they turned into the Ballerina Ballroom Cinema of Dreams. The cinema was filled with bean bags for seats and punters had to hand over a cake at the ticket desk to get inside. This year, however, the venue is unavailable, so Swinton and Cousins are taking their eccentric show on the road.

"We found ourselves without the Ballerina as a location for this year and so decided to make ourselves nomadic," she said. "Bricks and mortar can, after all, be greatly over-estimated in their importance to making culture available and alive for people."

This is the third playful film festival that Swinton and Cousins have collaborated on. As well as the Ballerina Ballroom last August, they took over a Beijing cinema in March, turning it into a Scottish forest. The Scottish Cinema Of Dreams, as it was dubbed, was visited by ambassadors and Chinese star Maggie Cheung.

For their latest quixotic odyssey the duo are inviting volunteers to join them to help haul the 37-tonne cinema between August 1-9. The full list of films to be shown is being kept under wraps until the end of the month, but roads will be a major theme.

Swinton and Cousin's moveable movie house is a "Screen Machine" - a portable cinema on wheels rented from Regional Screen Scotland, an offshoot of Scottish Screen, to promote cinema culture in isolated and rural areas.

Cousins said: "I don't think they ever expected it would be used in this fashion. We are going to take it places it has never been before."

Two of the screenings have been revealed: one is a documentary about dragging a large object up hills in the name of art, while the other is a classic, spooky road movie without any cars.

The former is Burden Of Dreams, the documentary charting director Werner Herzog's attempt to make Fitzcarraldo, which centres upon the re-enactment of the hauling of a massive paddle steamer through the Amazonian rain forest. The latter is Night Of The Hunter, the expressionist masterpiece starring Robert Mitchum, right, and described by Cousins as "properly dreamlike and surreal, just as we like our films."

If Swinton and Cousins have their way, their latest project will redefine the whole concept of "road movies".

"Road movies are often about men in cars in America, but we are going for something quite different," said Cousins. "A lot of our travellers are children, or women, or on foot, or in the Middle East or the frozen north or Japan. Our roads aren't motorways, they're back roads."

Swinton said she hoped the venture would help break people's preconceptions of what cinema is and, more importantly, where it should be.

"Cinema belongs everywhere and with everybody," she said. "More and more, the possibility, the memory of smaller picture houses of all shapes and sizes becomes blocked by our dependence on the multiplex for a big screen experience. We suggest that it is a relatively simple thing to challenge this exclusive dependence.

"We would like to encourage those with a will to do so to make similar ramshackle interventions, to spread the cinematic wealth, to claim film for themselves and celebrate the innate joy at the heart of a film fan's film-going."

The festival has received £9000 funding from EventScotland. Tickets will be available at www.thebooth.co.uk