At the hall in Nan Hua High School, four African teenagers are singing the popular 1980s xinyao song Voices From The Heart (Xiao Ren Wu De Xin Sheng) by home-grown music veteran Wu Jiaming.
They enunciate the lyrics effortlessly in perfect Taiwanese-accented Mandarin.
Below the stage, 420 Secondary 2 students sit listening in rapt attention.
For the four teens, however, singing in Mandarin is not unusual. They can also speak fluent Mandarin, write essays in Chinese and recite Chinese poetry.
This, despite coming from Malawi, one of the poorest countries in the world with a gross domestic product of about 1 per cent of Singapore's.
Aged 15 to 18, they have all lost either one or both parents. They are in town on an eight-week school exchange programme organised by the Singapore African Children Care Centre, a local non-profit body that aims to build homes for African children and provide them with education.
You can catch them today at Telok Ayer Hong Lim Green CC, where they will perform Chinese opera.
Next month, another 21 orphans from Swaziland, aged eight to 15, will join them for a performance at the Kallang Theatre.
They will perform African cultural songs and dances, Chinese mask-changing and Chinese martial arts, as well as sing xinyao hits such as Friends Forever (Xi Shui Chang Liu) by Liang Wern Fook and Starry Sky (Xing Kong Xia) by Eric Moo.
Proceeds from ticket sales will go to their orphanges in Africa.
As part of their trip here, they will also visit 42 schools to share their stories and their Chinese learning journey.
Nan Hua Secondary 2 student Nadya Ng, 13, says, after watching the xinyao performance last Tuesday: "Hearing them speak Mandarin and recite the poems was very inspiring. It really encourages me to take every opportunity to improve myself."
Mrs Thai Mok Jee, 51, the school's vice-principal, adds: "Given the orphans' background, learning Chinese must have taken twice, if not three times the amount of effort, compared with students in Singapore.
"I hope they will inspire my students to make the most of the opportunities around them to learn Chinese."
So how did these African youngsters get so good at Chinese? Through passion and hard work, they say.
The four who are in town attend Yuan Tong School in Malawi, where they are taught English, their African mother tongue and Chinese by teachers from China and Taiwan.
They are also taught agriculture, mathematics, science, history, geography and art.
Chinese, they say, is picked up mainly through rote learning.
One of them, Calvin Murowa, 15, who began learning the language at age eight, says in fluent Taiwanese-accented Mandarin: "In the first year, we were taught in our native language. After that, all the Chinese lessons are in Mandarin."
He entered the orphanage at age six after his father died in a car accident. His mother died from malaria soon after.
For an hour each day, he would copy sentences from textbooks and the teachers would explain what each sentence meant.
Says Murowa: "Whenever we wrote a word wrongly, we'd have to write the correct version 50 times."
Another orphan, Blessings Scale, 15, adds: "At first, I thought the Chinese characters on the blackboard were pictures.
"If we didn't pay attention, the teacher would make us stay in a half-squat position (zhan ma bu) for 30 minutes."
Mr Colin Goh, 50, secretary-general of the Singapore African Children Care Centre, says the orphanage was founded by a Taiwanese and believes the children will benefit from learning Chinese.
"All the students there must learn Chinese and the teachers there have their own teaching methods," he says.
"These might sound harsh to us, but coming from their background, being able to learn Chinese is considered a blessing."
Outside of school, the orphans read Chinese books, from folk tales to tomes on science and politics.
During their time in Singapore, they also write diary entries in Chinese every day.
Asked if the language is hard to pick up, all four teens respond with a resounding "yes".
But they soldier on because they believe mastering Chinese will improve their prospects.
China is Africa's largest trading partner and the Financial Times reported that trade stood at US$210 billion (S$261 billion) last year
Says Murowa: "Understanding Chinese will make it easier for me to find work and earn more money."
He hopes to be a lawyer, while Scale aspires to be a diplomat.
Since arriving on June 26, the orphans have visited Tanjong Beach in Sentosa as well as various hawker centres.
Scale says of roti prata and laksa, his favourite local fare: "They are spicy and the flavours are great. I'll never get tired of eating them."
Says Chinese opera advocate Nick Shen, 37, who has been training the four orphans in Chinese opera three times a week since their arrival: "They are truly amazing and remarkable."
Adds the former MediaCorp artiste, who is now a freelance actor: "Even though they sometimes train with me from 2 to 9pm, they never complain of being tired or bored. Their attitude is simply the best."