Chinese actor Wang Deshun swims, skates and works out in the gym just like any fitness buff. Last year, he acted in more than 10 movies and television dramas, mostly in supporting roles.

But the charismatic octogenarian shows no signs of slowing down. If he is not working on a film set, he is doing a fashion shoot or exercising.

In 2015, a bare-chested Mr Wang, with flowing silver hair and beard, strode down the catwalk, showing off his well-toned body.

Those 60 seconds on the fashion runway turned him into an overnight sensation, earning him the moniker "China's hottest grandpa".

His schedule these days is packed with work commitments and he has no plans to retire despite being well over the statutory retirement age. In China, men retire at 60 and women, at 50.

This year, the government is due to unveil plans to raise the retirement age for the first time since the 1950s. The retirement age will possibly be raised to 65 for men and 55 for women over the next five years.

"I have never thought of retiring. I will retire only if I can't work anymore," Mr Wang told The Straits Times on a film set in the outskirts of Beijing recently.

"But there's always someone asking me to do this and that," said the grandfather of a two-year-old girl.

Born in 1936 in north-eastern Shenyang, Mr Wang started out as a streetcar conductor, then a worker in a military factory, and eventually became a stage actor in 1960, when he was 24. In 1985, he uprooted his family to move to Beijing where he became a mime artist. He and his wife, now 74, have a daughter, 48, and a son, 42.

A decade later, he moved on to another form of performance arts known as "living sculpture".

In 2000, after his peers retired, he began working in film and TV.

And at the ripe old age of 79, he became a runway model.

And if anyone is curious about how he manages to keep in such tip-top condition, Mr Wang firmly declares that it is his work.

To him, keeping fit is what he does for his work as a TV and film actor, and it has been a habit born out of necessity over the decades.

A lot of physical training is required to be a mime artist; and a living sculpture, who usually goes on stage with an almost naked body sprayed with bronze paint, cannot afford to show any flab.

"I don't work out for health, neither is it for longevity. It's entirely for my work," he said.

To stay in shape, Mr Wang spends two hours daily in the pool and gym. No dieting, he said.

"I eat anything and I love meat," he said. "Some people use a scientific formula to eat; To me, that's like feeding animals, not living (a life). Eating is a form of enjoyment and I want to enjoy life."

Reminded about his runway walk, Mr Wang said it was a one-off affair. He has declined invitations that followed, including those for fashion shows overseas.

Mr Wang's son explained that his father did it as a favour for a former student who was working with Chinese designer Hu Sheguang.

"They had a male model whose body was not well toned and my father was asked if he could stand in," said the younger Mr Wang.

That completely unplanned modelling stint at Beijing's 798 Art Zone propelled Mr Wang to instant fame and attracted tens of thousands of new followers on his Weibo, the microblogging platform.

"People found it refreshing. They didn't know an old man at age 79 can still walk with that kind of vigour," he said."The walk that didn't last more than a minute was actually an accumulation of 30 years of training and hard work."

Mr Wang is no stranger to modelling, having taught catwalking some 30 years ago in one of the first modelling schools in China.

Being a stage actor, he explained, his style of modelling is to get his students to express their emotions, unlike in Europe where models remain expressionless to bring attention to the clothes they are wearing.

"(In 2015) on the runway, I was bare-chested. What I wanted to express was a mental state. Not a particular piece of clothing," he recalled.

Asked if he has any advice for young people who are in awe of his physique and his active lifestyle, he refrained from giving any.

"My motto is, you have to live your own lives. You live your life according to what's most comfortable to you," he said.

"There's no such thing as being too early or too late to do something. When you feel like it, just do it. It's possible you will succeed."