Darren Clarke has been drawing flab-bergasted second glances around Durban Country Club this week after shedding 40-plus pounds over the winter.
And even though he has stepped down from golf's heavyweight division, 45-year-old Clarke insisted he now packs a much harder punch.
The 2011 Open champion looks slimmer yet feels stronger than he has for years, courtesy of a comprehensive diet and exercise programme drawn up by a Dublin fitness guru.
Clarke has lost six inches off his waist and dropped several shirt sizes, leading to a complete wardrobe change and a bonanza for his local Oxfam shop.
Confirming that he had disposed of more than a hundred pairs of trousers, Clarke went on: "I've hung onto some as back-up but I've literally had to replace everything in my wardrobe.
"It's a medium now," he said, impishly fingering the collar of his polo shirt on the practice range as he prepared to swing into action in tomorrow's first round of the Champions Tournament in the sweltering South Africa summer.
A chance meeting with Dublin-based Jamie Myerscough at an outing he hosted for the Duke of Abercorn at Rockmount GC just outside Belfast last October sparked this dramatic change.
Asked what had motivated him, Clarke bluntly replied: "I was too fat!"
Frustrated after fading out of contention during the closing stages of the Dunhill Links Championship and several other tournaments, Clarke mentioned it to Myerscough, chief executive of the Educogym in Dublin, during the fund-raiser.
"We got talking about it during the round and Jamie said 'Right, I'll help you'," the Ulsterman explained.
"I lift very heavy weights and food has changed. I'm taking supplements and all that carry-on, which I hadn't done before.
"I see him five or six mornings a week at 7.00 on Facetime. Jamie's in Dublin and I'm in my gym at home. There's no cardio, it's all weights, and I'm in and out of the gym in 30 minutes.
"When most people lose weight, they lose strength as well. But I've gone the other way. I've lost weight and got twice as strong."
After losing "nearly three stone" in less than three months, he now weighs well below 14 stone. Asked what he had to give up, Clarke said: "Sugars. I eat low (sugars) and low fats. That's not to say I didn't have the odd pint or two over Christmas.
"I was getting too big and too tired. I actually played nicely at the Dunhill but made mistakes in the final five holes. It was the same old thing. That's what I've been doing for a few years.
"There have been a few poor swings or whatever but, obviously, a certain degree of that would point towards fatigue, so a lot of what I've been doing was just to get me stronger and fitter."
Meanwhile, fellow Ulsterman Graeme McDowell has been honoured by the Golf Writers Association of America for his accommodation and insight with the media, winning the ASAP Sports Jim Murray Award.