Sprinter Timothee Yap never expected that a schoolboy crush would eventually lead him to the Olympic Games.

Grinning sheepishly as he revealed the "real reason" he joined Rosyth Primary School's track and field team 12 years ago, Yap said: "The girl was my classmate for a year and I liked her, but we changed classes the next year. She was in the track and field team, so I joined as well."

Speaking to The Straits Times on the sidelines of a training session at Kallang Practice Track, Yap admitted that the object of his affections ran faster than him at the time.

"When I first joined, I wasn't even sure if I could make it to the national schools finals," he said.

"I didn't reach the finals until secondary school."

Come Aug 5, however, Yap will don national colours at the Rio Olympic Games, where he will compete in the men's 100m race.

Yap revealed he learnt of his wild-card entry to the Games when a message flashed on his phone while he was playing an online basketball game with a friend on Monday night.

The 21-year-old said he went on the Internet to confirm the news only after finishing the game instead of keeping his friend waiting.

"Sportsmanship what!" he quipped.

Turning pensive, Yap added: "I feel very humbled by the opportunity given to me, and very touched that there are so many people supporting me."

Just a year ago, things were very different for the former 400m hurdler as he failed to qualify for the SEA Games.

"I was disappointed, because competing at the SEA Games on home ground is a once-in-a-lifetime experience," said Yap, who had tried to qualify for the 110m hurdles and 4x100m relay events last year.

"But I guess it turned out to be a blessing in disguise, because not qualifying for the SEA Games gave me a longer off-season.

"It allowed me more time to focus on building up my strength and power, so that I could improve faster this year."

Yap made the switch from hurdles to sprinting last year, having found it difficult to resume 400m hurdles training after completing his national service in May last year. He clocked a personal best of 10.62sec in the 100m at the Santo Antonio International Meet in Lisbon last month.

"My fitness had dropped a lot and it was very hard to get back on track," he said.

"But through NS, I improved on strength because of all the physical training, so I decided to try the shorter events."

But the law undergraduate at the National University of Singapore has another hurdle to cross before he makes his Olympic debut - the 18th Asean University Games (AUG), which begins here on Sunday.

Yap will captain the Republic's AUG athletics team, and has been pencilled in for the 100m and 200m sprints, as well as the 4x100m relay.

While he has hopes on winning a medal in all three events, Yap revealed another goal: to clock a new personal best at the AUG.

"I think I'm in good condition, so I hope I can continue this good form," he added.

"The best-case scenario is if I land new personal best timings at both the AUG and the Olympics.

"It's not impossible."