Neither mezzo-soprano Samantha Chong, 31, nor soprano Pham Khanh Ngoc, 29, imagined that they would grow up choosing professional opera singing as their careers.

But they did and are passionate about what they do.

Both women have been billed as rising stars in the opera scene here after Chong, a Malaysian, won the first prize in the inaugural Singapore Lyric Opera-Asean Vocal Competition last year. Pham, who is Vietnamese, was the first runner-up.

They will be showcasing their powerful vocals at the Singapore Lyric Opera's (SLO) annual gala concert, Unrequited Love, next month at the Esplanade Concert Hall.

The concert will feature music from opera classics performed by renowned singers such as soprano Jessica Chen and tenor Kee Loi Seng, and young talents such as Chong and Pham.

There will also be performances by the SLO Chorus and the SLO Children's Choir. Leading the SLO Orchestra will be conductor Jason Lai.

Pham remembers precisely when she knew she wanted to be an opera singer - at age 21.

For two years before that, she had concurrently pursued two disciplines: a university degree in economics and a vocal performance certification from the Ho Chi Minh City Conservatory of Music.

"After two years, I realised in 2009 that music was my true love," she says.

Still, she completed her economics degree in 2010 and received her first certification from the conservatory a year later. She continued lessons at the conservatory and, by last year, had attained a master of art degree in vocal performance.

The only child of a former volleyball coach father and a retired singer mother, both of whom are in their 60s, Pham says she has her parents to thank for her career choice.

Her mother had studied vocal performance in the same conservatory as she did and was a professional singer. Her father wooed her mother after falling in love with her voice during one of her performances.

Pham says: "Their story is very romantic. Because music was what brought them together, they have always been supportive of me choosing to be an opera singer."

They exposed her to music from a young age. She began piano lessons when she was six and soon developed a love for classical music. She read up on composers and memorised their works.

In her teenage years, she listened to opera classics on YouTube and found herself wishing she could sing like that.

Her hopes became a reality when she took to the stage as an opera singer at the age of 25.

Chong's growing-up years saw her immersing herself in music by joining school choirs.

She enjoyed those experiences and wanted to further her interest by studying music.

When she was 20, she moved to Hong Kong and began her studies at the Academy for Performing Arts. There, she earned a bachelor of music degree, followed by a master of music degree.

"I enjoy being on stage very much," says the multi-talented Chong, who also emcees and performs in plays.

The youngest of four children, whose father has died and whose mother runs a business, Chong says her parents always "trusted" her to make her own career decisions.

She will be performing two songs at the upcoming gala concert: Dopo Notte from Handel's Ariodante and Parto, Ma Tu Ben Mio from Mozart's La Clemenza Di Tito.

These were the same arias she performed at the SLO-Asean Vocal Competition last year. She says of the songs: "They are both technically demanding and showy pieces. I've been singing them for years and they are among my favourites."

Chong, who studied Italian, German and French, says "something magical goes on in my brain" when she performs.

"I am processing the lyrics in Mandarin, but I'm singing the song in its language. It happens simultaneously," she says.

Pham, who is a guest vocal coach at the Ho Chi Minh City Conservatory of Music, will also be performing two numbers: Tornami A Vagheggiar from Handel's Alcina and Bel Raggio Lusinghier from Rossini's Semiramide.

She is looking forward to the concert. "It is uncommon for a Vietnamese woman to do what I do because opera is not the most popular kind of music in my country," she says.

"But being an opera singer is so meaningful to me as I get to sing beautiful melodies and I experience many emotions when I perform.

"There are many challenges and difficulties, but I try my best and I hope Vietnamese people and people of the world will enjoy this form of music."