The inadvertent Olympian is 31, married, as slender as a sapling and as gentle as her event is severe. She has also been doing something she never thought she ever would: collecting newspaper clippings. She's in the news, you see. No, wait, she is the news.

Neo Jie Shi never dreamt of the Olympics and yet she will run the marathon at the Rio Games and so her father, 59, a lorry driver, is doing what excited fathers do: He wants her to cut out clippings. He wants a memory. Maybe he will look at them in 10 years and smile at the wonder of sport and the fast feet of his child.

Athletes are obsessed by the Games, they measure themselves by the Games, but not Neo. She was not fixated on Rio but was just another no-coach, gadget-free runner striding fast down the roads of Jurong. Her best time was 3hr 9min 57sec and the Rio cut-off was 2:45. The Olympics was too distant, the Olympics was never why she ran. "No," she says, "I (never) thought of qualifying. It seemed quite far for me."

The unplanned Olympian became a runner through what else but accident. She ran cross-country at 18 because she was a basketball player who wished to improve her "stamina and fitness on court". She kept running because it was a "simple hobby", where you "put on shoes and run anywhere", at any speed. But please don't think she runs just to watch sunsets: "During races... when I see there's a competitor ahead, the competitive instinct inside me will just kick in."

She ran because in a solitary sport could be found a sense of community. The road is only as lonely as you make it and she says running "allows me to socialise with my friends". And she ran because in the marathon, this unforgiving test of lungs and heart, the "greatest opponent" is not just the shimmering stretches of never-ending tarmac but "yourself".

The unexpected Olympian is a fabulous story because it is sport as surprise. People come to a Games from everywhere and in every lovely way. In her case, she ran the Standard Chartered Marathon Singapore last year, finished 10th, and was informed by a fellow marathoner, Mok Ying Ren, that the top 10 runners had met the entry qualifications for Rio. "I was surprised," she laughed, "and couldn't really believe it."

The unintended Olympian had earned her way and yet she wears modesty like a light perfume. Even when confirmation of her place in Rio came a few weeks ago, she did not exult. "It doesn't (still) occur to me that hey, I am an Olympian. Maybe only when I'm there and finish my race I will think I am an Olympian. Right now I am just an athlete training consistently and working towards a goal."

The Olympics changes people, it alters lives, it transforms their world. Neo is no longer just part of this city's mob of runners, she is in a sweaty class of her own. She is quizzed on radio, heralded in print and appears on TV and you can hear the incredulity in her voice as she contemplates her different life. "The first magazine to interview me was a men's magazine (Men's Health)," she laughs.

Her hero is a civil servant in sneakers, Yuki Kawauchi, a gifted Japanese runner who has a full-time job. And now, in a lovely coincidence, even if not as fast as him, she is a version of him - a full-time employee at GP Batteries who has made it to the Olympics. A woman inspired and yet now inspiring herself.

In recent months when she went running on the streets where she was once no one, now people saw someone. Other runners would greet her, wish her, cheer for her. "It was quite heart-warming," she says. At the National University of Singapore, a girl told her she was an inspiration and Neo says, softly, innocently: "I thought wow, I didn't know I can inspire someone."

All this attention was "overwhelming", but all this attention had purpose. "I understand that going to the Olympics is good for the sport," she says. It is a way to highlight distance running, especially this 42.195km race which is a run, a test and a life lesson on breaking through invisible walls. It was a way also to turn the spotlight on women. "There's a lot of hidden potential (in Singapore)," she says and there is an authority to her statement for she is proof of it.

Running did not make Neo but it has helped reshape a woman who was awkward and shy as a child. "Growing up I did not feel good enough," she says. "I just felt I'm not as good as my peers." But running was her equaliser, running gave her esteem. "Running," she says "gave me a different kind of confidence, it taught me about overcoming adversity. Running a marathon can be quite challenging and I know if I can overcome this challenge I can overcome any challenges that come along in work or in life."

Now running has taken a charming athlete from Jurong to Rio, to an Olympics, to mix with Ethiopians and Kenyans, to compete with the extraordinary and realise that in her own way she is no longer ordinary. It's why when she returns home someone should offer her a pen, a piece of paper and ask for a historic inscription. Neo Jie Shi, as of two weeks ago, had never given an autograph in Singapore.