PERSONAL LIFE: Born in Turin, this model, singer and actress has been married since 2008 to former French president Nicolas Sarkozy. Shot to fame in the late Eighties, and reportedly had a relationship with Eric Clapton. Has two children, five-year-old Giulia and 16-year-old Aurelien. Said to be worth well over $18 million.
SKIN CARE: Incredibly smooth and clear skin, considering her years of smoking. Appears to have had Botox and fillers, but says she uses Hydranorme, a French face cream by La Roche-Posay. Besides, it's not all about looks: "Wrinkles without wisdom are boring. I want to become mature. I want to become wise," she says.
HAIR: She entrusts her famous chestnut locks to leading stylist David Mallett. A cut and blow dry with the man himself in his Paris salon costs about $465. Other clients include Kate Winslet, Charlotte Gainsbourg and Sharon Stone.
EXERCISE: Has a personal trainer, Julie Imperiali, whose approach is holistic, combining yoga and Pilates, as well as focusing on the pelvic floor muscles, which Imperiali calls "the floor of the house".
Bruni has upped her game with the passing years: "I do ballet, Pilates, yoga. When I was younger, I would just sit around smoking and eat McDonald's."
DIET: Imperiali says that Bruni has a little of what she fancies - a very French approach - and is also said to enjoy a "Biooster Grog", an orange and herb beauty drink served at The Gabriel Hotel in Paris. Bruni loathed putting on more than two stone when pregnant with Giulia. "I'm kind of tall, with good-size shoulders, and when I am 40 pounds overweight, I don't even look fat, I just look ugly."
STRANGE AGEING: She vapes. "It's delicious. It's so nice that I think it has to be toxic. You never find something very delicious that is completely untoxic, right?"
BEER AND $370 FACIALS
Claudia Schiffer, 47
PERSONAL LIFE: Discovered aged 17 in a Dusseldorf nightclub, she's appeared in Guess adverts and been the face of Chanel. Was engaged to magician David Copperfield, before marrying film director Matthew Vaughan in 2002, with whom she has three children. Apparently worth over $74 million.
SKIN CARE: That porcelain skin is drenched in expensive skincare. "I go to the Sisley spa at Claridge's. The best facial is the Supremÿa Facial ($370-plus for 90 minutes). It uses muscular massage and lymphatic drainage to completely relax muscles in the face and eliminate toxins"
HAIR: Her tumbling golden locks are carefully tended with products she helped to develop. "I use Schwarzkopf Essence Ultime Lotus Blossom + Color Protect in the shower to make my hair colour last, whilst also giving it a really healthy look."
EXERCISE: "I work out by doing long walks with our dogs, tennis, yoga or Pilates."
DIET: "I start the day with an espresso then eggs." While she eats, she listens to music: "I love to listen to Eighties music.
"I am all about health, rather than diet. For example, I eat less dairy and less gluten when trying to be healthy. I find this works way better than totally cutting things out."
STRANGE AGEING: "This isn't scientifically proven, and I can't back it up, but some people say drinking beer makes hair shiny and strong. You're better off with a do-it-all serum - but a little beer can't hurt!"
SKIPPING AND MAPLE SYRUP DETOXES
Naomi Campbell, 47
PERSONAL LIFE: The famously firey Campbell was the first black woman on the cover of French Vogue, aged 18. Said to be dating tobacco boss Louis Camilleri. Worth $55 million.
SKIN CARE: "I'm obsessed with this face cream called Rescue. I've been using it every day."
HAIR: Decades of hair extensions led to a form of alopecia. She's now more careful and it has grown back.
EXERCISE: Stays honed with the help of yoga and Pilates. She also enjoys skipping. "The rope is great for your face."
DIET: A vegetarian, in 2014 she told Harper's Bazaar that she does two or three juice cleanses a week - which doesn't leave much time for normal food.
STRANGE AGEING: Thrice-yearly detox involving a cocktail of maple syrup, cayenne pepper, lemon juice and water and nothing else: "The most I've ever done it for is 18 days."
TEQUILA, SAUNAS AND PROTEIN SHAKES
Cindy Crawford, 51
PERSONAL LIFE: After a brief marriage to Richard Gere, she wed businessman Rande Gerber in 1998. They have two staggeringly handsome children, Presley, 18, and Kaia, 16. Cindy appeared on Vogue covers 50 times and is said to be worth over $139 million.
SKIN CARE: Swears by skin oils. There's one in her range, Meaningful Beauty, which she launched with face smoother to the stars Dr Sebagh.
HAIR: Those famous, tousled locks have been subject to years of heated tools. In 2016, she said: "I'm trying to be kinder to my hair and not heat styling it so much."
EXERCISE: Cindy first hit the gym aged 20 and has rarely left it. "I work out with my trainer, Sarah Hagaman, three mornings a week." She pays close attention to her neck. "Over 20 years ago, I saw a woman doing exercises for her neck...if you keep those muscles toned, it helps preserve your jawline."
DIET: "I try to be 80 per cent good, 80 per cent of the time." The day may start with green tea, a protein shake and a restrained half of a muffin. A controlled regime, but one that is clearly paying off. She won't touch wine, but likes the odd tequila "on the rocks with lime and ice".
STRANGE AGEING: "I try to go into an infra red sauna for 20 minutes once a week. My homeopathic doctor suggested I get one because it's good for detoxing."
PASTA AND POLE DANCING
Helena Christensen, 48
PERSONAL LIFE: Born in Copenhagen, Christensen won the Miss Universe Denmark title in 1986. Has been on the cover of Vogue six times, dated Michael Hutchence, then was with actor Norman Reedus for five years and had a son. She is now dating musician Paul Banks. She is an acclaimed photographer, as well as a model and businesswoman.
SKIN CARE: "My grandmother has the most beautiful, softest skin. And all she ever uses is water, soap and Nivea. I've used hundreds of different products, amazing-smelling oils, scrubs and serums...but every time I visit my grandma, I go back to soap, the water and the Nivea," she told Allure magazine.
HAIR: Goes to various U.S. based stylists and recommends two salons based in Copenhagen. "Zenz only use organic hair colour and have their own great line of natural products, including a beautiful oil called Deep Wood No. 99, which I use on my hair and my body."
EXERCISE: Gets fit with pole dancing. "I used to wake up and sprint, which is a great way to spark your metabolism. In my mid-30s, I started boxing. My newest exercise is pole dancing, and it's the hardest thing I've ever done. The upper-body strength you need is mind-blowing."
DIET: All these women admit to highly moderated diets, rather than claiming fast metabolisms. "I'm not the kind of person who will limit myself to any kind of food. I could not live without bread and pasta. I eat butter and drink whole milk. And I'm obsessed with Japanese food and Moroccan stews."
STRANGE AGEING: Says her weirdest beauty habit is "using coffee grounds and papaya flesh as exfoliators".