He was to have started serving his two-month jail sentence for bigamy on Wednesday.
But Tan Tee Wee, 48, was found dead in a condominium apartment in Orchard Road on the same day.
The cause of death is unknown and police are investigating, Shin Min Daily News reported yesterday.
An undischarged bankrupt, Tan was the chief executive officer of events management company Roxwell when he married Esther Tan Wee Yee at the Auckland Marriage Registry in New Zealand in February 2010, while he was still married to Goh Geok Tin.
He pleaded guilty to bigamy in November and was out on $10,000 bail as he wanted to spend time with his children before commencing his sentence.
According to the Chinese daily, the Cairnhill Circle apartment where he died is not his last-known registered address.
A close friend of Ms Tan told the paper that he had been living with another girlfriend, who is said to reside in the Orchard Road area.
He has three children by Madam Goh, aged 12 to 18. They registered their marriage in October 1988.
Tan came to know Ms Tan some time in 2000 through work-related matters.
They entered into a relationship the following year.
Tan told Ms Tan about his first marriage and assured her that he was going to end it - even producing documents to show her that he was filing for divorce.
About 10 years into their relationship, they decided to get married. Ms Tan did not know he had not divorced Madam Goh.
Tan chose to marry Ms Tan in New Zealand as he knew that he could not do so in Singapore.
He told Ms Tan that they had to tie the knot there because he had unresolved "tax issues" in Singapore that were related to Madam Goh.
The same reason was given when she asked him why he had stated that he was "never married" in the particulars of the New Zealand marriage certificate.
Ms Tan, 39, lodged a police report in November 2013.
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