In the letter, which starts "Dear Daddy", socialite Gigi Chao asked her father Cecil to treat her partner Sean Eav as "a normal, dignified human being" — the pair have been together for nine years and are reported to have married in 2012 in France.
"I know it’s difficult for you to understand how I could feel romantically attracted to a woman; I suppose I can’t really explain it either. It just happens, peacefully and gently," she wrote in the letter, which was published in the South China Morning Post on Wednesday and circulated to other Hong Kong media.
Her plea came after property developer Chao, 77, who refuses to recognise that she is a lesbian, was reported last week to have doubled the "marriage bounty" on his daughter to HK$1 billion ($130 million), after an initial offer of HK$500 million two years ago.
The first sum attracted 20,000 candidates, with the bizarre dowry attempt making international headlines.