Half a century ago, they were schoolboys in white and blue uniforms running around the quadrangle, getting into fights and being sent out of classrooms.
Today, one is a deputy prime minister while others are chief executives, doctors, lawyers and businessmen.
But yesterday, their positions in society did not matter as they gathered with old friends at a reunion nearly 40 years since they left school.
Some 150 men who graduated from the Anglo-Chinese School (ACS) in 1975 returned there dressed in white and blue "uniforms" at a dinner last night.
About 30 former teachers also turned up for the event on the ACS (Barker Road) premises, to commemorate 50 years since the men first met in Primary 1.
The cohort, which turns 57 this year, includes Deputy Prime Minister and Finance Minister Tharman Shanmugaratnam, and former attorney-general Steven Chong.
Singapore's eighth and current Attorney-General V.K. Rajah is also from this batch.
Other prominent old boys include Judge of Appeal Andrew Phang, Esplanade chief executive Benson Puah and Mr Desmond Lim, chairman of the Les Amis Group.
Yesterday, some of the men toured the school grounds, where their classrooms and old blocks used to stand.
They also re-lived school assembly sessions and sang the National Anthem together in the school auditorium.
They spent the evening reminiscing about their younger days, looking at old photographs and catching up on each other's lives. Many of them had spent 12 years at ACS.
They also did their part for charity by raising nearly $400,000 in funds, most of which will go towards social causes like the Yellow Ribbon Fund and Singapore Children's Society.
The sum includes $30,000 to help retired ACS teachers in financial need.
The group hopes to collect more donations in the weeks ahead.
Mr Tan Peng Chin, who headed the organising committee, said: "We didn't just want to have a good time, but also wanted to encourage our classmates to give to society."
The lawyer, who has three children - two daughters aged 28 and 23 and a son aged 26 - was at ACS from primary school to pre-university.
Recalling how Mr Tharman was active in sports such as hockey and cricket in secondary school, he said: "When we heard he was Education Minister, we thought it was a good move because he was an all-rounder in school.
"I remember the friendships made in school more than anything else. My best friend in Secondary 1, who now lives in the US, flew back specially for the gathering."
Mr Leonard Tan, a classmate of former attorney-general Steven Chong, said: "I could not have imagined how so many of our batchmates would go on to become very prominent people. We were all regular boys then.
"We rushed out every recess to the quadrangle to play games like sepak takraw, hantam bolah (Malay for hitting ball), chatek, basketball."
The father of two, who works in corporate marketing, added: "As boys, we were quite mischievous. For instance, when we got sent out of the classroom, we would wander off and disappear. I have the greatest memory and respect for the late Mr Earnest Lau who was an incredible English teacher and who also caned me for fighting in class.
"Our teachers disciplined us, and we deserved it."