'Ladies of London' star and British aristocrat Annabelle Neilson dies at age 49

Annabelle Neilson, the former star of the Bravo reality series Ladies of London, has died at age 49.

People confirmed the British socialite's passing on Tuesday. However, details surrounding her death were not immediately available.

According to Page Six, sources say Neilson died last Thursday. However, the secrecy and lack of information about Neilson's passing even had some of her friends confused, with some believing -- or hoping -- that it may have been a hoax, since Neilson was reportedly 'active' on Instagram on Saturday.

The former model appeared on Ladies of London for two seasons between 2014 and 2015. Among her final Instagram posts was a poolside photo shared on June 17.

"In Spain catching some rays #sun," she captioned the picturesque image.

Born of an aristocratic family (her mother Elizabeth is a marquesa), Neilson was very well known in the highest British social circles. She was notably very close friends with supermodel Kate Moss and late designer Alexander McQueen.

Neilson opened up about her distress upon McQueen's suicide in 2010. She was the last person to see the fashion icon alive.

"He was my brother, my boyfriend, my soulmate. Most of the time people called me Mrs McQueen. Quite often we were sharing a bed," she told the Daily Mail in 2015.

She continued, "The truth is I was happier with Lee [McQueen's given first name] than with anyone else. He asked me to marry him towards the end and I said no. I wish now that I had said yes," she added.

In that same interview, she also spoke warmly of her long friendship with Moss, adding that the she loved the supermodel "like a sister."

"Kate is my best mate and I love her like a sister. Yes, she's an icon but to me she's just Kate."

She added, "We fight over stupid things, then we kiss and make up. We share clothes, we share everything and her fame has never been an issue. She always looks out for me and I look out for her. We've got each other's backs."

The socialite also discussed her own personal struggles, telling the Daily Mail that she became a heroin addict at age 16 but eventually found sobriety.