Tuuli, madly, deeply: Tuuli Shipster is truly shipshape

'Tea? Coffee? I thought we might sit outside on the terrace Sunscreen?' The daughter of a British diplomat, she has such a ladylike, jolly manner ('Marlborough was a fantastic school. I loved it!') that I keep having to remind myself that she takes her clothes off for a living. She's made a speciality of posing for outré shots – nude in heels, nude in black bodypaint, nude save for a few strategically placed sweeties – but being a nice girl, she married the photographer. 'Of course I like to be desired – by my husband,' she says. 'Those pictures are made very much within the relationship. And, you know,' she sighs naughtily, 'he's very persuasive.'

When Madeleine Tuuli Shipster met John Rankin Waddell on an Elle Macpherson Intimates lingerie shoot in 2003, they had both always been known by their middle names ('Tuuli', meaning little wind, was a nod to Finland, where her father was posted when she was born). Rankin was already one of the top photographers in the world, known for his high-gloss, highly sexed, hyper-perfect fashion images and celebrity portraiture. He is 16 years her senior (he's 43, she's 27) and in charge in some ways: their apartment's stark black and white décor was, she says, 'very much Rankin's choices'. But she has a lot of fun being his muse and galloping rings around him – literally.

A keen horsewoman, Tuuli spent most of their honeymoon in Spain last year racing off on Domingo, 'a crazy, fast gelding'. She started riding aged four in India, where her father took her to the polo stables near the embassy. 'So I'm always asking: "Can we get a horse in this shoot? Let's have me naked on a white horse again!" ' Tuuli fetches the book Tuulitastic – A Photographic Love Letter, made while they were engaged, and finds the photo of her playing Lady Godiva, reclining bareback, beautifully naked and totally hairless (of which more later) on a horse. 'As Rankin made me lie back, I did think, "Really? Really? This could hurt if she bolts" '

While we're chatting, Rankin is next door in their bedroom, still asleep. When they met she was 20 and had just deferred her place at LSE – again. 'I was going to read politics and economics but I was enjoying modelling so much – meeting people and travelling – that I thought, "Oh well, I'll have a gap life!" ' She has a breezy manner that masks, I think, true grit. Her father's diplomatic postings took the family (she has a younger brother, Robin, whose band Wara played Glastonbury this year, and an older sister, Katya, who works in publicity for Penguin) to Moscow, Finland, India and Zambia, where, she recalls, 'a curfew was in place and once we had to run out of school and lie down in the back of the car'. To hide from gunmen? 'Just because my parents were worried about violence, nothing bad.'

Her father, now retired, worked for the Foreign Office on missions including a Hans Blix-style assignment in Iraq, prior to the 2003 invasion. Is he a spy? 'Well, he's had a very interesting career,' she grins, before apologising that she can't talk about it and miming a gun blowing her head off. It is, she insists, a lovely coincidence that she was chosen to be the silhouette on the cover of the 2008 James Bond novel Devil May Care. She also played one of Bill Nighy's Santa Girls in Love Actually, 'playing the saxophone and dancing out of time'.

It was Tuuli's game attitude that first attracted Rankin. 'She just gave a lot of chat, she was sarcastic back to me,' he recalls fondly, as he emerges, blinking, at 11.30am. 'Some models you can't banter with. You make a joke and you can feel them pull back.' Tuuli says her agent, Sarah Doukas, had told her to give as good as she got. Rankin also appreciates the way she sees their work as art. 'Some girls have ideas about how they want to improve society, and say they're just there to make money before they do something "worthwhile". OK, so what I do isn't worthwhile?' He growls and shakes his head, a David Bailey de nos jours. Bailey's book Trouble and Strife, shot with his then wife Marie Helvin, was clearly an inspiration for Tuulitastic. 'I love Bailey,' says Rankin. 'He's like my...' he trails off trying to find the word. 'Frenemy?' suggests Tuuli. 'No, the opposite! A bromance, that's it.'

Tuuli and Rankin didn't get together for two years after they met, and it wasn't always a romantic courtship. Soon after the Macpherson advert they had another assignment together for Arena magazine – her first nude shoot. Rankin rang her up and talked her through it. 'So the circulation of Arena is about X thousand. So at least double that amount of people are going to see this shoot. Out of that number about 20 per cent are men who are going to wank over you. How do you feel about that?' Tuuli shrieks at the memory. 'It freaked me out.' Was he winding you up? 'A mixture. He likes getting a reaction.' She went ahead with the shoot, and never looked back. She always shaves herself 'completely' so as to be ready for any job. 'It's best to get it all off, then you feel more confident.' Her latest shoots with Rankin have seen her painted gold and wearing a metallic bikini, and also posing in a burnt-out train as 'a serial killer-type, this moody, mean S&M girl'. Has Rankin ever gone too far? 'No. I don't know what I'd draw the line at because it hasn't happened yet.'

She tries not to think about what her parents, now living in Winchester, make of it all. 'I'm sure it's hard for them, but it's my choice. They've been very good at letting go.' Her grandmother was once rung up by a reporter wanting to know what she made of Tuuli's 'raunchy' career. 'At the time it was upsetting for my family. I'm sure they'd have loved to say a lot to me, but they've been nothing but supportive.'

It was while in Winchester that Tuuli befriended Phil Nevin, one of the founders of the Caterpillar Run charity. He recruited her to take part in this year's Virgin London Marathon as part of The Caterpillar, a formation of 33 socialites tied together by rope. Their number included Richard Branson's children and Princess Beatrice, and they raised £250,000 for Children in Crisis. Running, she says, 'changed my body in a positive way, it really lengthened it'. She eats what she likes, cooks Hummingbird cupcakes and does British Military Fitness twice a week on Hampstead Heath. She thanks genetics for her figure. 'I've always been very comfortable with my body.'

For the beach she favours 'old-fashioned, glamorous' swimwear, as modelled here, shot in a house formerly belonging to actor William Holden (The Bridge on the River Kwai, Sunset Boulevard) in Palm Springs. 'That was a location to really get you in the mood,' she says. 'Just totally fabulous.' Or to put it another way, totally Tuulitastic.

(profile-models.com)