Tara Palmer-Tomkinson died of 'natural causes'

Tara Palmer-Tomkinson was found dead in her London flat last week at the age of 45. Photo / AP

Tara Palmer-Tomkinson died of natural causes and "did not have a brain tumour", her sister has said.

Santa Montefiore posted a series of tweets thanking people for their support in recent days following the death of the socialite at the age of 45.

But the author added that she wanted to "clarify" a few things and referenced a coroner's report released on Wednesday into the death of the former It girl.

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."

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."

Her funeral is due to be held on February 27.The former "It girl" and reality TV star was found dead in her west London flat last week.

In a statement her family have said: "We would like to thank the many people who have contacted us about Tara following her untimely death. It has been a source of great comfort to know how loved she was by so many people.

"Tara died peacefully in her sleep due to a perforated ulcer and peritonitis.

"Those that knew and were close to Tara knew that there was no retreat to a "dark place" as some have disappointingly sought to suggest. In the last few weeks Tara was happy, positive and making plans for when she recovered her health.

"As usual she had been busy with the friends and family she loved, and who loved her in return. She was in communication with her family and others of whom she was fond over her final weekend and had spent a lot of her time recording music and playing the piano in her apartment - a sure sign that she was happy and feeling good.

"Tara's funeral will be on the February 27. This will be a private moment for family and close friends to grieve and we would ask that our privacy at this time is respected. We will miss Tara very much and will never forget the joy, love and humour she bought to our lives."

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 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".

What is a perforated ulcer?

When a stomach ulcer splits the lining of the stomach open, it is known as perforation.

This can be very serious, because it enables the bacteria that live in your stomach to escape and infect the lining of your abdomen (peritoneum). This is known as peritonitis.

In peritonitis, an infection can rapidly spread into the blood (sepsis) before spreading to other organs.

This carries the risk of multiple organ failure and can be fatal.