Sun was born in Singapore on July 23, 1978. She attended Nanyang Primary School, St. Margaret's Secondary School, Raffles Girls' School, Saint Andrew's Junior College, and Nanyang Technological University, where she obtained a bachelor's degree of Marketing in 2000. During the college, she wrote her first song titled "Someone", which later appears on her 2002 album, Start. She also attended LWS School of Music, and her vocal talent was discovered by her music Teacher Lee Wei Song, who later introduced Sun to Samuel Chou, the chairman of Warner Music Taiwan at the time.
In May 2011, Sun married with Nadim Van Der Ros, who is a Dutch-Indonesian and founder of The Good Bean Consultancy. They had actually secretly registered their marriage in March 2011. In October 2012, Sun gave birth to her first child.
