"ARE you dancing?" demanded Tilda Swinton, striding across Edinburgh's Festival Square in a man's kilt and shirt, a black cloth bag of badges swinging from her long pale arms.
• Square dance: actress Tilda Swinton and film writer Mark Cousins lead the flash mob in the Laurel and Hardy dance at Festival Square, Edinburgh, yesterday. Photograph: Phil Wilkinson
When it's a Hollywood star asking, the answer – judging by the number of folk who turned up yesterday to bust some moves with the Bafta-winning Chronicles Of Narnia actress – must be yes, I'm dancing.
Swinton, who lives in Nairn and is a patron of the Edinburgh International Film Festival, which draws to a close this evening, yesterday launched her new charity, the 8 Foundation, with what can only be described as a flourish.
Gathering several hundred willing participants under the shadow of Edinburgh Castle, she led them in a soft-shoe shuffle known as At The Ball, by the Avalon Boys, originally performed by Laurel and Hardy, in an effort to create a "flash mob dance", where a group suddenly and spontaneously start dancing in a public place.
The instructions, disseminated online, were simple: watch the Laurel and Hardy clip, turn up at 11am and give it a whirl. The reason, declared Swinton, was "in pure unabashed celebration of doing something as a group and looking like dafties".
It's certainly not the sort of thing you see in Lothian Road every day, as the confused people in the bus queue, not to mention the befuddled passers-by, would testify.
Barbara and Brian Matthews, a couple from Kirkcudbright in their late fifties who have crammed in 17 films during their week at the Film Festival, came along to see what all the fuss was about.
"We're fans of Tilda Swinton, she's a fantastic actress, so we thought we'd try it," said Brian. "I've never danced in public before though."
In the middle of the square, four colourfully dressed women, who on any other day might look like bona fide Morningside ladies, diligently rehearsed their moves – swinging their hips and waving their arms as the clock ticked towards 11am. Had any of them done anything like this before?
"Do we look like we've done anything like this before?" one squawked back, to the sound of raucous laughter. Why had they come then?
"It seems like a fantastic idea," said Heather Mohieddeen, 49. "It doesn't matter if you look like a fool. Scotland's far too reticent when it comes to these kind of things."
Swinton, meanwhile, flitted through the crowd, dispensing 8 badges along with hugs and smiles.
Lending support was the father of her children, Scots playwright and artist John Byrne, as well as the man the tabloids refer to as Swinton's "toyboy lover", 31-year-old artist Sandro Kopp, who had dressed for the occasion in a pair of lederhosen. Even screen legend Brian Cox turned up, describing the event as a "very Tilda thing".
According to Mark Cousins, the film writer and former director of the EIFF, who with Swinton has set up the 8 Foundation, the charity's mission is to inspire children to celebrate the age of 8 as their "movie birthday", by being given DVDs as gifts, for example, and to allow more children access to films through schools, arts organisations and community groups. It was inspired by Swinton's son Xavier, who at the age of 8 asked his mum what people dreamt about before movies were invented.
As the clock struck 11am, the music started, far too quietly, and folk began swaying in an embarrassed, I'm-not-sure-about-this-after-all sort of fashion. But suddenly the volume was cranked up, and Swinton and Cousins started dancing energetically, performing the moves initially put together in the 1930s by the silent film stars. The crowd followed, and suddenly around 300 total strangers were dancing together, twirling each other around, laughing at the ridiculousness of it all.
My own attempt at a soft-shoe shuffle was not an unqualified success, although this may have been because I chose to perform it in 3in heels. Having tried it out in the office beforehand, I found myself carried along by the half-remembered steps, and a nice lady to my right who kept giving me encouraging glances.
By the time it got to the funny hip swivel bit, I was positively enjoying myself, and stopped moving only because the latter half of the dance appeared to require a partner, something I forgot to bring.
At the end there was cheering, and Swinton and Cousins shouted "Again!" and the music started up anew.
Afterwards, Swinton declared herself delighted by the whole event. "It was astounding," she said, still catching her breath. "So much better than I could even have imagined. It's so liberating to do something that feels like it could be completely impossible."
Using language only movie stars can get away with, she described the event as "the flower on the seed" of the 8 Foundation, and the flash mob event as "reliably random".
One dancer, George Barlow, who was with his wife and friends, went further. "It was fantastic," he said. "It should become an annual event."
Just quite what Lothian Road bus queues would make of that remains to be seen.