The Queen is in mourning after her best friend and first cousin Margaret Rhodes died aged 91 after battling a short illness.
Her Majesty, 90, is said to have visited her friend at her home in Windsor, Berkshire, when she became ill earlier in November.
Buckingham Palace said last night that the Queen is aware and that it is a ‘private matter’.
Mrs Rhodes appeared on a number of documentaries about the Queen – who does not give interviews, reports Camilla Tominey at the Sunday Express.
The Queen (right) and her first cousin Margaret Rhodes (left) remained close after growing up together
The pair remained close and would meet up when the Queen was in Windsor after church on Sundays.
A royal source told the newspaper: ‘The Queen will be devastated to have lost her best friend. She grew up with Mrs Rhodes and they had so much shared history.
‘They remained close throughout the Queen’s reign and Her Majesty continued to be a regular visitor at Mrs Rhodes’s Windsor home until very recently.
‘It is such a sad loss for Her Majesty, Mrs Rhodes’s family and everyone in the royal household. She was an extraordinary woman.’
Mrs Rhodes was a first cousin of Elizabeth II and was the youngest daughter of the 16th Lord Elphinstone and his wife Lady Mary Bowes-Lyon.
Lady Bowes-Lyon was a sister of The Queen Mother, Queen Elizabeth.
This photograph shows a young Princess Elizabeth, Princess Margaret and their cousin Margaret Elphinstone, later Rhodes
During World War II, Mrs Rhodes – who was born in London – lived at both Buckingham Palace and Windsor Castle when she worked as a secretary for MI6.
Before the Queen’s 80th birthday ten years ago she gave an interview and confirmed that the Queen would not retire, despite rumours.
In 2013, she was asked whether she was excited about the upcoming birth of Prince George.
She famously replied: ‘Not terribly, everybody has babies so I wouldn’t get terribly excited about it.’