It’s September 17. 11am. Three days before the first episode of Strictly Come Dancing Series Six. A side street in central London.

A paparazzo lurks behind a parked car. Across the road, through the swing doors and down the stairs, Lisa Snowdon and Brendan Cole are sweating, sweating, sweating. Lady Marmalade booms out of the speakers; already being played for the ninth time this day. Snowdon, for the future edification of eight million viewers, is having her virgin induction into the ways of the cha-cha-cha.

“F***!” she wails, as she hinges the wrong way on the offbeat and kicks Cole in the shins.

“I agree on ‘F***!’” Cole says, wincing.

With fewer than 79 hours to go before the inaugural show, the rigours of the Strictly Come Dancing schedule on the celebrity contestants are physically apparent. Snowdon’s back aches. Her feet are covered in shiny pink pressure points. She has a long scar on her leg – “heels” – and a purple and green bruise the size of an iPhone on her thigh. On Monday, Brendan Cole’s girlfriend, Zoe, came in to watch rehearsals. Snowdon, trying to impress, stepped on her own foot, in heels, and her shoe filled up with blood. “I thought, ‘Style it out, style it out,’”

Snowdon says. “You’re a Strictly girl now. I didn’t. Even. Miss. A. Beat.”

Yesterday, inadvertently, Cole punched Snowdon in the face just before the big lift. Today, every time they approach the big lift, Snowdon stalls. “I’m psychologically traumatised! It’s like Vietnam!” she hollers, as the dance grinds to a halt again.

“My instructor used to hit me on purpose,” Cole says, slyly. “He used to dig his nails into my back. I’m a little more modern in my approach.” He grabs a large, wooden pole that’s propped up in the corner of the studio and chases Snowdon – a model and TV presenter also known for going out with George Clooney – around the room with it, pretending to hit her. They squeal with laughter.

Later, they sit on the floor, with coffee and chocolate cake, speculating on what is happening with the other contestants, and what will happen when the show starts in earnest. They have only met the other contestants once – during a photo shoot, at the show’s launch – and discuss them as if they were oddly distant, mythic beasts.

“Apparently, Jodie Kidd’s kicking off because all the others have dance experience,” Snowdon says, licking icing off her fingers. “And Christine Bleakley was saying she was insecure around the other women. I don’t know why. She’s gorgeous.”

“John Sergeant will stay in for ages because he’s had loads of publicity and everyone thinks he’s funny,” Cole says, with the calm wisdom of an old Strictly hand. Cole has been in the show since the first series, which he won with Natasha Kaplinsky. “They will expect stuff from us – because it’s me. And because you have dance experience,” Cole continues. “John Sergeant will be getting eights just for turning up. And we’ll be sweating, but just getting sixes. You’d better be ready for it,” he warns Snowdon. “It is going to be tough. Although,” he adds, brightly, “if Craig [Revel Horwood, one of the judges] gives you s***, just bring up that he wanted to be a rent boy.”

Elevenses over, Snowdon and Cole get back to rehearsals. While she dances in earnest, at first Cole merely feints his way through the moves, working away from her, at the periphery of the dancefloor. At the moment when he must first touch Snowdon, however, he snaps into the routine with an almost alarming intensity – steaming across the floor like a centaur going into battle, silent except for his shoes hissing against the parquet.

Editor's choice

• U2 at Nou Camp Stadium, Barcelona
• The 50 Best Movie Villains
• The 15 golden rules of theatre etiquette