Tara Palmer-Tomkinson has been found in her flat in South Kensington after police were called to the scene by London Ambulance Service today at lunch time.
The death is being treated as unexplained at this time and her next of kin have been called.
A spokesperson for London Yard said: "Enquiries into the circumstances are ongoing. The Coroner has been informed."
Palmer-Tomkinson had recently revealed a year-long battle with a brain tumour, which was discovered in January last year. The growth on her pituitary gland was discovered during a blood test and she was later diagnosed with a rare auto-immune disease as a result of future tests.
Shortly after her diagnosis, she spoke about how it had changed her outlook on life. "I’m not the person I was, I’m much calmer. I don’t go to places like Ibiza because the party world scares me," she explained to The Daily Mirror. "It used to really matter what people thought and said about me. Now, it doesn’t bother me whether people write that I’m off my face, on my face, in my face, whatever. It’s all pretty trivial compared to [this]."
A former columnist, model and reality TV star, the 45-year-old had appeared on I'm A Celebrity Get Me Out Of Here and Fame Academy, and wrote four books, including Infidelity and Inheritance.
A well-connected socialite who moved in Royal circles, she spent many winter holidays skiing with Princes Harry and William in Klosters as a child, and remained close to them into adulthood.