Singer-songwriter Lew's national service stint has given his music talent the greatest exposure so far, but it has also led him to turn down two potential big breaks.

A Singapore Police Force National Day music video he sang in went viral last year.

Separately, he was talent-spotted by the producers of the popular TV show Sing! China and also by its American counterpart, NBC's The Voice, through his own YouTube videos, but he passed on those golden opportunities.

"The first reason is NS," says the 20-year-old, whose name is Lewis Loh. He would not be able to commit to filming schedules as he will complete his full-time national service as a singer in the Singapore Police Force band only in December.

"The other reason is that I want to focus on my original songs. If you do those competitions, you get exposure, but I still feel that I have a lot to learn with my own music."

The video of him singing last year's National Day theme song, Our Singapore, was posted on the Singapore Police Force's Facebook page and shared more than 450,000 times. It was highlighted by Prime Minister Lee Hsien Loong as a "beautiful rendition" .

Apart from that, Loh has been steadily building up an audience for his original, soulful folk-pop tunes through his YouTube channel as well as at regular shows that take place whenever he is off-duty. In February this year, he released a single and music video, Two, and plans to release another, Loved You So, later this month.

On Sept 2, he will perform a live set, backed by a full band, at the Esplanade Outdoor Theatre, a show that is part of the Esplanade's Mosaic Music Weekend.

At the show, he will sell thumbdrives containing four demo versions of new original songs that he recently recorded.

While he has been singing and playing the guitar since he was 13, he made up his mind to focus on a music career after taking up a summer programme at United States music school, Berklee College of Music in Boston, at age 16.

It was also around that time that he started to develop what has become his signature husky voice.

"I used to suck so bad at singing," says Loh, who takes inspiration from British singer-songwriters such as Ed Sheeran, Passenger and Birdy. "And then puberty came and my voice changed."

Born and raised in Hong Kong, Loh would visit Singapore only during Chinese New Year, but has been living here on his own since he enlisted in national service in December 2014.

His Singaporean parents are divorced. His businessman father lives in Hong Kong while his mother, a housewife, lives in the United States. His twin sister is studying in Switzerland.

Last year was a watershed year in his musical development. In March, he took part in the National Arts Council's Noise Singapore Music Mentorship programme and was taken under the wing of 53A singer Sara Wee and singer-songwriter Vanessa Fernandez.

It was Wee who gave him his first public gig at restaurant/live music venue Timbre in May that year.

As the most promising mentee, he was awarded the programme's Noise Singapore Award for 2015.

"I actually learnt a whole lot, but the highlight of that whole thing was just meeting people. Prior to Noise, I didn't have friends for three months."

Loh intends to plunge full-time into his music career after national service. His plan is to release an EP and a full-length album before going back to enrol in Berklee to study songwriting in September next year.

Realistic about his prospects in the fickle music industry, he says: "In this line of work, most of the time things don't go as planned and a lot of things have to do with being in the right time and place.

"But I'm trying not to stress and worry so much about long-term plans. I just want to focus on building my portfolio and a solid foundation in music, even if it takes a long time. I'm still learning and growing every day."