Princess Diana's letters may fetch over $125,000 at auction

In letters, she also talks about weight & self-esteem insecurities, recurring depression & despair

An archive of 33 intimate letters written by Princess Diana, providing firsthand insights into her troubled marriage and personal insecurities, is expected to fetch over $125,000 at an auction.

The handwritten letters addressed to Diana's confidante Carolyn Pride Bartholomew were written from between 1978 and 1997. The archive documents the seldom-explored years of Diana's from January 1980 to January 1982.

This period includes the royal engagement and wedding to Prince Charles, the three-month-long honeymoon, Diana's first pregnancy and initial year of marriage, according to RR auction house in the US.

The letters touch upon some of the most widely speculated aspects of Diana's life including her tumultuous marriage, her doubts and an indirect mention of Camilla, now married to Prince Charles.

She also talks about her weight and self-esteem insecurities, recurring depression, and despair over press intrusion.

"The weight is down to 9 1/2 stone - got into a size 29 jeans yesterday, instead of 32! So I am feeling much healthier but don't imagine a slender gal - 'cause there is still a lot to come off," the princess wrote in one of the letters.

The penned correspondence archive consists of 33 main pieces: 28 handwritten signed letters from Diana, encompassing 109 pages over 60 sheet; 26 are signed "Diana," one signed "D," and one signed, "me".

Eight include the original hand-addressed envelopes, several with her initial "D".

Diana met Carolyn at West Heath School when they were 12 -years-old.

They shared a dormitory then and became flatmates seven years later at 60 Colherne Court. Demonstrative of Diana and Carolyn's intense bond, Carolyn would be Prince Harry's godmother and Diana godmother to her son Jack.

The online bidding begins on August 18.