A large collection of private letters from Princess Diana will sell at Cheffins in Cambridge on January 5.
The letters date to between 1984 and 1993 and are expected to sell for a combined £15,000 ($18,373), with individual estimates ranging between £300 ($367) and £900 ($1,102).
The letters reference some key moments in Diana's life
They originate from the collection of Cyril Dickman, a former steward at Buckingham Palace who was a close friend of the family.
The correspondence includes references to some of the most pivotal moments in Diana's life - including the birth of her sons.
She writes: "William adores his little brother and spends the entire time swamping Harry with an endless supply of hugs and kisses, hardly letting the parents near!"
She also writes of losing her mother: "Her death came as a great shock, but it has meant an enormous amount to receive messages of support such as yours."
Dylan Mander, a spokesman for Cheffins, said: "Cyril's grandson came in and said while he was going through everything he found all of these amazing letters from Princess Diana.
"The letters explained all different things - how Harry had been naughty at school and how Harry was adored by his brother who would not stop kissing him.
"It is incredibly rare to have letters from Princess Diana with such a personal touch to them.
"She would not have had friends in the sense we do so you could say Cyril Dickman was one of her closest friends."
