Tara Palmer-Tomkinson, a former London socialite and the god-daughter of the Prince of Wales, has died at the age of 45.
She had been diagnosed with a brain tumour last year.
A spokesman for the Metropolitan Police said: "Police were called by London Ambulance Service at approximately 13:40hrs on Wednesday February 8 to an address in Bramham Gardens, SW5.
"A woman, aged in her 40s, was pronounced dead at the scene.
"At this early stage, the death is being treated as unexplained.
"We are not treating this death as suspicious. The coroner has been informed and the next of kin has been informed."
Palmer-Tomkinson revealed in November that she was being treated for a non-malignant growth in her pituitary gland and had expressed fears that she would die after being told of her condition by doctors.
She told the Daily Mail: "I went to the doctors to talk about my latest blood test results when I got back from skiing in January. I said: 'What does this mean? Can you translate it?' And the doctor said: 'As I suspected, you have a brain tumour'.
"I got terribly frightened. I started thinking 'I'm going to die, I'm going to die. I've only got a couple of weeks to live.' Stuff like that."
At the time, Palmer-Tomkinson, who has battled drug problems in the past, also revealed that was suffering with an auto-immune disease which had caused tiredness, joint pain and acute anaemia.
She appeared on reality TV series I'm A Celebrity... Get Me Out Of Here! in 2002 and came second, as well as several other TV shows including celebrity specials of Blind Date and A Place In The Sun.
Palmer-Tomkinson was diagnosed with the tumour last January after she returned from a ski trip.
She was a regular on the London party scene in the 1990s and made headlines for her social life, frequently appearing in the pages of both society and celebrity magazines.
During her years in the spotlight, she was a newspaper columnist and television personality and had a close relationship with the royal family, attending the wedding of the Duke and Duchess of Cambridge in 2011.