Tara Palmer-Tomkinson, the socialite and 1990s "It girl", has been found dead by police at her London home aged 45.
A coroner's report on 15 February said that she "died peacefully in her sleep due to a perforated ulcer and peritonitis."
The statement said that media reports of her retreating to a "dark place" in the hours before her death were untrue.
In a string of tweets, Palmer-Tomkinson's sister, the novelist Santa Montefiore, also denied reports that she was suffering from a brain tumour and corrected other elements of the media's reporting on her death.
Prince Charles, a family friend, said in a statement that he was "deeply saddened" by the news.
"Police were called by London Ambulance Service at approximately 13:40hrs on Wednesday, 8 February to an address in Bramham Gardens, SW5," the statement said.
"A woman, aged in her 40s, was pronounced dead at the scene. Next of kin have been informed.
"The death is being treated as unexplained. At this early stage, police are not treating the death as suspicious. Enquiries into the circumstances are ongoing. The Coroner has been informed."
Palmer-Tomkinson, a high society figure who was at the wedding of Prince William and Kate Middleton, rose to fame in the 1990s through her regular appearance in celebrity magazines and a ghostwritten column about the London party scene in the Sunday Times.
In 2002 her stock rose higher thanks to her appearance on the first UK series of I’m a Celebrity... Get Me Out of Here!, on which she finished as runner-up to Tony Blackburn.
She told the Daily Mail in November last year: “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.”
Palmer-Tomkinson was also a pianist and occasional singer and released this song on her YouTube channel in 2012.