DR Miriam Stoppard is lying on an exercise ball in the middle of her living room demonstrating how she tones her arms and strengthens her tummy muscles.
Her long, shiny hair flows down and her flawless skin glows as she goes through her daily workout.
Then she bounces up, looking fresh and energised and invites me to peer at her hairline for tell-tale signs of a face lift.
There are none. So how on earth does this 75-year-old grandmother look like a woman 30 years younger?
That has been the question on millions of readers’ lips since the Daily Mirror columnist had a new photo taken for her popular Health Focus page.
So I visited Britain’s favourite doctor and best-known agony aunt at home to ask her the secret of her youthful looks.
“I had my eyes done when I was 54 but I haven’t had any other plastic surgery,” she says. “No Botox, no fillers. Nothing.”
“I’ve inherited great genes, I follow a simple beauty regime, I eat healthily and exercise every single day.
But I do have one secret weapon – my 11 grandchildren. They are the love of my life and they have given me a second lease of life.
“And love really is an amazing vitamin.”
Dr Miriam, OBE, has been helping readers since 1997 as well as writing numerous books and TV series, working with more than 100 charities and leading health campaigns.
Her own problems, such as her second divorce from playwright Sir Tom Stoppard after 20 years and two sons, have helped her understand others’ heartache.
Now happily married to Sir Christopher Hogg, she also had a terrifying brush with death when she was struck down with blood poisoning four years ago.
But now fully recovered and fitter than ever Miriam hopes her simple health and beauty tips will inspire millions of other women in their seventies and beyond.
She said: “I like to use an up-to-date picture and had this one taken for my 75th birthday.
“I’ve always been very honest about my age and I’ve written so much about cosmetic surgery that I had to be upfront when I had it done myself.
“The plastic surgeon advised me to have only my eyes done. He uses a special technique that involves lifting the muscles of the face as well as the skin.
“That’s why the results are so long lasting. It was around the time I was going through the menopause.
“My attitude is, as long as you are not expecting plastic surgery to change your life, renew your relationship or help you find a new partner, and you research it thoroughly, that’s your choice.
“I’ve been lucky and inherited good skin from my dad’s side of the family.
“All his sisters had wonderful, peachy skin, even in their 80s. But I’m also a dermatologist so I know how to look after my skin.
“I haven’t had soap and water on my face since I was 15.
“Soap de-fats the skin, it strips off all the moisturising sebum that’s produced, making it less supple and often flaky.
“I use a pack of Simple facial wipes to cleanse with, then I put on a Chanel lifting serum and a moisturiser with a Sun Protection Factor of 25.
“When I was 22 I got really badly sunburned and since then I have worn a total sunblock every day on my face, neck and décolletage.
“I’ve been using the same make up for more than 20 years – Chanel and Mac. Chanel might sound glamorous, but it’s not that expensive and lasts for ages.”
But Miriam insists looks are a reflection of how we are on the inside – and she is “jolly healthy”.
She says: “My parents were keep fit fanatics long before people knew the importance of keeping fit.
“They were both gymnasts and cyclists and my sister and I learned to swim early because my Mum just chucked us in the pool.
“They were interested in nutrition. We had three veggies with every meal, fruit every day, and lots of fish – because we were pretty poor and fish was cheap then. So, by accident, I learnt to eat healthily.”
Like most women, Miriam has battled her weight. She explains: “I was at a family do two years ago and noticed a couple of relatives had lost weight.
“I did the Weight Watchers plan online because I needed the impetus and a few tips on things like portion size. It took me over a year but I lost two stones and, nine months on, I haven’t put it back on.
“Now I eat vegetables, which I steam with soy sauce, and chicken, turkey or fish for lunch.
“In the evening I have a very light cooked meal, maybe prawns or squid with some rice.”
Daily exercise is also a must.
Miriam says: “I have always done some form of exercise, even when the children were small.
“I can remember sitting on my exercise bike in the kitchen while the boys were having their tea so I didn’t have to leave them.
“Now I do a programme of intermittent high intensity exercise (short bursts of hard rowing or cycling interspersed with gentler recovery periods) and need just 15 minutes every other day.
“I have my Swedish ball in the sitting room so I can just roll it out and do core-strengthening exercises whenever I get a chance. But to get exercise into my daily routine I walk everywhere – to meetings, to the theatre, well over 20 miles a week.
“I’d been addicted to high heels all my life but 10 years ago I gave them up for trainers so I could walk properly – energetically.”
“Now I’m fitter than I was twenty years ago. In terms of stamina and strength my body feels about 40 and in my head I’ve never got older than 38!
“Exercise is the greatest anti-ageing tool we have got – it gets the oxygen pumping around your body and nourishes every single cell, in your skin, your brain, everywhere. Even my memory is better than before.”
It all means Miriam has plenty of energy for her 11 grandchildren from her two sons and four step-children.
She says: “Nobody ever tells you that you are going to have two bites of the cherry. You think those days of being broody and loving babies and looking after them are gone. But they’re not.
“When your grandchildren come along you discover that tremendous love that you had for your own babies – but doubled, re-doubled.
“It just ambushes you. When your first grandchild arrives you feel ‘My God! There it is again!’
“Love is an amazing thing. It makes you feel you can climb mountains and swim oceans for the loved one…and that great drive and desire comes flooding back with grandchildren.
“They are the light of my life.”