A retired surveyor who lived in a modest two-bedroom flat and enjoyed shopping at car boot sales has bequeathed £6m to a children's hospice.
Mr Witham loved making money from business but spent little
Jack Witham, from Southampton, Hampshire, amassed his fortune in property and died in 2004 aged 79.
Almost all of his estate went to Naomi House Children's Hospice, Winchester.
Friends said Mr Witham never gave any indication of his wealth and only spent money on the essentials and a season ticket for Southampton Football Club.
He loved football and classical music and enjoyed making money from business but never spent it, they said.
The chief executive of Naomi's House, Ray Kipling, said: "It's a complete bolt out of the blue and fantastic news.
"We knew nothing about it until we received a letter from the Jack Witham's executors which just said we had been remembered in his will.
"We didn't know Jack Witham in his lifetime and the bequest is the largest we have ever had."
Mr Kipling said the money would be used to extend the 10-bed hospice and build a dedicated centre for six gravely ill teenagers that would be called Jack's Place in memory of the generous benefactor.
"The money has allowed us to do something brilliant," he explained.
"The will said it had to be a specific project and we had been thinking about doing this for some time as medical advances mean that young people who are in Naomi House are living longer and they needed somewhere to stay."
The hospice has now launched an appeal to raise a further £6 million that is needed to finish Jack's Place.