When his 10-year-old son Orion was diagnosed with autism seven years ago, Mr Stuart Ang would not have dreamt that he would one day play in a concert with his son.

But yesterday, that became a reality for the music enthusiast.

The pair, who played the French horn, joined about 100 other musicians as part of The Purple Symphony to perform for over 1,200 people, including Prime Minister Lee Hsien Loong and Deputy Prime Minister Heng Swee Keat.

Mr Ang, 37, who is self-employed, told The Straits Times: "This is our first time performing together. I could not have imagined that Orion could come so far."

He said Orion, who has a short attention span, picked up the French horn only in March.

"Some people say it's one of the hardest instruments in the world to learn. It takes practice and he practises every day," said Mr Ang.

The concert at the Esplanade was held in conjunction with the fifth anniversary of The Purple Symphony, Singapore's largest inclusive orchestra. It features musicians with and without special needs.

The Purple Symphony, which was started by the Central Singapore Community Development Council in 2015, has grown from 80 to more than 100 musicians.

Yesterday's concert was also held in commemoration of Singapore's bicentennial and featured locally composed and arranged pieces.

Ms Denise Phua, Mayor of Central Singapore District and adviser to The Purple Symphony, said the orchestra was proof of what individuals with and without special needs could achieve together.

She said: "These five years have not been easy, but it was worth every minute and every effort to put together Singapore's largest inclusive orchestra from scratch.

"We want to show others that our musicians can use their talents and abilities to inspire Singaporeans through their music, and be a beacon of inclusivity for others."