A Lotto player has confessed to winning $55million (£40million) 10 years ago without telling anyone from their family.
The lucky winner from California, in the US, also said they did not donate any money to charity.
The punter believes they "would be broke" if they had decided to share their money with family and friends.
They added they did not help their sister with the win as they "do not like her or her husband".
The confession came in a letter to The Moneyist, a financial agony uncle who gives advice on topics including inheritance, wills and divorce.
In the letter, the anonymous winner wrote: "About 10 years ago, I won over $55 million (£40million) in the California lottery. I never told my parents or my sister, or anyone for that matter.
"I have kept a low profile. I did buy a new truck and a house, but I told them I was renting the house. Was I wrong to not tell anyone?"
They added that their parents would not have asked for anything, but they believe their sister would have suggested donating half of the sum to her church.
The self-acclaimed winner, who is now 67, continued: "I have not donated money to anyone or any organisation.
"I also do not believe in loaning money to friends and relatives, no matter what. If I did, I would be broke."
The punter, who signed off the letter as "Low-Key Lottery Winner", said they are "comfortable" with their life, do not have kids and their parents have passed away.
In the letter, they added: "I have not provided for my sister because I do not like her or her husband, and I have not spoken to her in over 10 years.
"She hopefully has no clue where I live, besides, my parents took her out of the estate before they died.
"She tried to do some horrible things to our parents, which I managed to put a stop to. Was I wrong in not telling anyone about my winnings?"
Responding to the winner, financial agony uncle Quentin Fottrell said California is among half-a-dozen of states that prevent lottery winners from maintaining total anonymity as their names are usually in the public domain.
It is not clear how the winner managed to remain anonymous, but there is a possibility that they have a common name.
But the financial agony uncle concluded: "Money cannot buy you authentic relationships with friends and neighbours, and it can’t buy you more time on the planet.
"For that reason, I see nothing wrong with living your life the way you want to live it, and resisting the urge to share the news with anyone, even and especially your family."
But Mr Fottrell said the winner should consider leaving money to charity once they pass away to make sure it does not go wasted and is put to good use.
