This is the smile that says Dame Mary Peters is on the road to recovery from extensive open heart surgery as she joyfully declared: "I feel alive again."
Northern Ireland's 1972 Olympic golden girl turned national treasure yesterday spent her first full day at home in Dunmurry following a six-hour NHS operation at Belfast's Royal Victoria Hospital and a spell of recuperation at the Somme Nursing Home in east Belfast.
Speaking publicly for the first time since her operation three weeks ago, the busy 79-year-old admitted she will not find it easy following doctors' orders to row back on her hectic schedule, fundraising for her Mary Peters Trust and supporting events in her capacity as the first lady of Northern Ireland sport over five decades.
"It has been a shock to the system," said Mary. "All the medical and nursing staff who attended to me at the Royal and in the Somme were marvellous. I couldn't speak highly enough of them.
"But from leading an extremely active life, on my feet sometimes 24/7, being confined to quarters, even for just a few weeks, was very difficult to come to terms with, more so even than the operation itself which, I'm told, took six hours, but I wasn't awake for that.
"It's been a success and, now I am home, I just want people to know now why I have had to turn down invitations and engagements for a time until I am fully recovered.
"Then I will be back at work, primarily on my Race to a Million project to secure the future of the Trust in order to aid future generations of young sportsmen and women.
"I have been given a second chance here and intend to make the most of it. Initially I was told that without the operation, my life expectancy would be no more than two years.
"Afterwards I was told it could have been as little as one. With the new heart valve I've been given, that has gone up to 10. I am determined they will be 10 good years."
That kind of information can be difficult to process, especially the initial prognosis. But the eternal optimist in Dame Mary took a typically pragmatic view.
The Munich Olympic pentathlon gold medal winner revealed she entered the imposing environment of a hospital theatre, for only the second time in her life, feeling trepidation but without fear.
"I had never been ill in my 79 years and only hospitalised once when I required surgery on an injured shoulder," Mary said.
"Knowing what this operation entailed I was a little apprehensive about being admitted, simply because of the unknown, but I wasn't afraid.
"I've always been active and wasn't looking forward to being out of action for any amount of time. I was told it was a six-hour operation. I have no recollection.
"I have always had this mechanism whereby I compartmentalise by shutting out thoughts of anything I don't want to do and replacing them with more positive ones.
"Like when I go on a long-haul flight, I never ask how many hours. I just shift my focus onto something else until we get there.
"So it never occurred to me that I might not come through the operation, despite the risks inherent in all surgery.
"I wasn't afraid because I've enjoyed a wonderful life. I've won an Olympic gold medal, served as Lord Lieutenant of Belfast, founded my Trust, provided Northern Ireland with an international-standard athletics track, with the help and support of the Telegraph's late, great sports editor Malcolm Brodie - it is his legacy, too - and been made a Dame and named a Companion of Honour by Her Majesty The Queen.
"I have made many great friends down the years and met so many people I wouldn't otherwise have had an opportunity to do so, had it not been for my athletic career and everything that came from that."
Mary counts Nelson Mandela as the most inspirational person she has ever met, in her role as an ambassador for an Olympic youth programme, aiding promising but disadvantaged athletes in South Africa.
She also formed a close bond with Princess Anne from their time together in the British Olympic team.
It is part of BBC Sports Personality folklore that when Princess Anne, the 1971 winner for her equestrian success, handed the 1972 trophy to her team-mate, Mary responded on live television to the nation: "Hasn't she kept it clean."
Their enduring friendship saw the princess fly to Bel fast to personally launch and endorse the Race to a Million at a City Hall banquet two years ago.
Moving in those circles, Dame Mary is not easily daunted.
Yet she revealed: "I was so unprepared for being in hospital. I expected to walk in and straight back out again in a matter of days and initially everything was going to plan.
"I was sitting up, welcoming visitors and telling them I would be out by the weekend.
"Then I had a setback when irregular heart rhythms were detected and I was back in bed hooked up to tubes and monitors again. I was in a low place those few days. Having blood taken and all manner of tests carried out was alien to me. I was in a state of shock.
"I hadn't asked for too many details about my operation so I was quite interested when a programme came on television about open heart surgery showing the same operation I went through.
"I was fine with it until the surgeon cut into the breast bone. Then I had to turn away.
"One of the nurses treating me said the effect on the body of such prolonged surgery was akin to being hit by a bus. That is when I realised what exactly I had come through. I wasn't in pain, which was a surprise in itself to my nurse friend, but there was a great deal of trauma to deal with."
It all began, Mary reflects now, with an unplanned check-up.
Unaware of any problems, she says: "In 2013 I opened a facility at Kingsbridge clinic on the Lisburn Road and was offered a full health check which showed a heart valve was not working as efficiently as it should.
"I was unperturbed. There were no noticeable symptoms and because I was fit and leading a healthy lifestyle, walking four miles daily, it didn't register with me that this could be something serious lying in wait up ahead.
"I carried on doing what I was doing, working for the Trust, fundraising, taking part in activities and then becoming immersed in my Race to a Million project.
"Then in January this year I came down with a bad cold. I was out walking and experienced a bit of a problem walking uphill.
"Soon after, I was at an event at the track, where there is a steep incline on the way out, and as I was walking away, I found myself becoming short of breath. I actually bent down and pretended to tie my shoelaces so no-one would notice, I hoped.
"This time I paid heed and made an appointment with my GP, who sent me to a consultant for cardiogram and echo tests. I spoke to a good friend who is a consultant, Malcolm Crone at the Ulster Independent Clinic, to seek his advice which was to go for surgery."
The Mary Peters Trust has an arrangement with the clinic whereby injured young athletes are fast-tracked for treatment to get them back into action as quickly as possible, an initiative funded by the Rory McIlroy Foundation.
But while undergoing the operation privately was an option, Mary chose to join the NHS waiting list, neither wanting nor expecting preferential treatment.
Eventually introduced to the surgeon who was to carry out her operation, Alastair Graham, at the RVH, he explained that an aortic valve had calcified, preventing blood from circulating as it should.
"It didn't matter that I had led an active and healthy life," said Mary. "There had been a gradual deterioration through age and because of the nature of the problem, there was no option but to open me up.
"Prior to surgery I had been told that without the operation, I would have a life expectancy of no more than two years. Afterwards, it transpired it might only have been a year. Now with my new valve, I've been told I could have another 10 good years ahead.
"I want to thank Mr Graham, his surgical team and the nursing staff at the Royal for giving me this gift of extended life.
"I have been working for the last two years to achieve my Race to a Million target, coinciding with my 80th birthday celebrations next June, and when my recuperation is complete, I look forward to rejoining the campaign with renewed vigour, knowing I am going to be well enough to see the project across the line.
"I am also looking forward to enjoying walking again.
"Towards the end of my stay at the Somme Nursing Home I was able to go outside and tentatively take my first few steps unaided down the road outside, using lampposts as a yardstick and going one further each day.
"My physio urged me not to rush things but I can't change the way I am. I was on a Zimmer frame at first and it bugged me.
"I received fantastic care from everyone at the Royal but it was an important step in my recovery to be able to leave and within a few days at the Somme, I blossomed again. Finally I had time to quite literally smell the roses.
"The staff there were marvellous, too, and I was cheered by the amount of cards and bouquets that began to arrive from well-wishers as word of my operation spread.
"I had visits from my fellow gold medallist Jim Kirkwood, a winner with the Great Britain hockey team at the Seoul Olympics in 1988, and who is also a director of my Trust, and from pole-vaulter Mike Bull who brought along an old black-and-white pic of us competing at Crystal Palace in 1972.
"But most all I have to thank my good friends Gillian Hetherington, Terry Crothers and Georgina McCloskey who have been towers of strength all the way through."
Gillian is executive manager of the Trust while Terry is a director and former BBC NI sport administrator and member of the NI Commonwealth Games council, recently retired. Georgina has been a long-time friend.
"They helped restore some normality to my life as I recovered in the Somme," Mary adds.
"I had television, my phone and iPad and began to draw up a to-do list for when I got home. I thought about writing my Christmas cards but then decided it would be a nice thing to do back at home.
"But I will have to take things gently for a time. I'll be having regular check-ups, no driving for six months, and no lifting - not even a kettle."
Mary smiles then at the thought of what her doctors would have made of her abseiling down the side of Belfast Castle in May in a Trust fundraiser when the extent of her condition was not yet known.
"I was scared clambering over the parapet and thought to myself 'Do you realise what age you are?' but it was an achievement and I was going to do it.
"I was then due to take part in a zip-wire challenge across the Lagan at the Queen's Bridge in August in aid of my Race to a Million but just before that I had treatment for cataracts in my eyes. The nurse said I wasn't to do any window cleaning or vacuuming for a while.
"I replied, 'What about a zip-line?' You can imagine the response.
"But that's me. I am not going to rest on my laurels when there is work to do. I have never failed in my life and I am not going to start now when we are so close to raising that million pounds.
"We are three-quarters of the way there and now the final push begins to hit the target by next June when we will have a special birthday celebration with star guests at Titanic Belfast."
At the age of 79, Mary's first major medical experience has been a whole new learning process, a rollercoaster of emotions.
Even getting ready to come home to her picturesque cottage on the outskirts of Belfast posed uncertainty for a normally outgoing personality.
"I needed to prepare myself mentally," Mary explained.
"I needed to get my confidence back for meeting people. It sounds irrational but I felt people would be looking at me, as if they knew I'd just had surgery, even if they didn't. It's in your head but going out to a local cafe for a coffee with Terry helped. I knew then I was ready to face the world again."
Always an inspiration, Mary now intends using her experience to encourage others to seek medical advice at the first sign of breathing problems, however minor they may seem.
"I would definitely say, go to your GP. It could be asthma or some other reason or it could be your heart needing a new part, like mine. Get checked out," she said.
"I am so grateful to have been given a second chance. Although it involves major surgery, six weeks is a short time to change you life for the better.
"People like Alastair Graham and his NHS staff are such experts. They know what they are doing and I would have no hesitation putting my trust in his hands again."
For information on how to donate to Mary's Race to a Million, go to www.marypeterstrust.org