Tara Palmer-Tomkinson died of natural causes and "did not have a brain tumour", her sister has said.
Author Santa Montefiore posted a series of tweets thanking people for their support in recent days following Palmer-Tomkinson's death at the age of 45, but added that she wanted to "clarify" a few things and referenced a coroner's report.
She wrote: "I've been so touched by the warm response to Tara's death. Thank you from the whole family. But I'd like to clarify a couple of points.
"Today the coroner's report states that Tara died of natural causes - a perforated ulcer. She did not have a brain tumour."
Montefiore added that "contrary to some reports, Tara was not the goddaughter of HRH the Prince of Wales".
She wrote: "Tara's good friends & family know that she was in high spirits in her last days. She had plans, trips & had written a moving new song."
She finished her stream of statements by adding: "Lastly there will be a fuller statement from the PT family later today. Thank you again."
The former "It girl" and reality TV star was found dead in her west London flat last week.
Last year she revealed her fear of dying after being diagnosed with a non-malignant brain tumour.
After finding out about the growth in her pituitary gland, she later spoke about also suffering with an auto-immune disease that caused tiredness, joint pain and acute anaemia.
In what is believed to be one of her last interviews, she told the Daily Mail's Weekend magazine about her quest to "make her family proud again".
Following the news of her sudden death, her close friends the Prince of Wales and the Duchess of Cornwall were among the first to pay tribute.
Charles and Camilla said they were "deeply saddened and our thoughts are so much with the family".
A death notice on page 26 of the Daily Telegraph was published last week, stating: "Tara Clare died peacefully in her sleep".
The piece also added that a private funeral is to be held.