A newly-found letter written by Princess Diana to a fan shows how badly the royal was hurting following the breakdown of her marriage.

Diana wrote the letter to a fan named Erika in 1995 after the woman got in touch to confide in her about her marriage troubles. In it, she says she recognises her pain and lack of self-esteem and commends her courage for speaking about her feelings. The date on the letter is 29 November 1995; just days after the princess spoke to BBC's Panorama programme about her marriage breakdown in sensational detail. It was in this interview that she revealed that her marriage had felt "crowded" as she felt there were three of them in it - herself, Charles and Camilla Parker Bowles, whom Charles is believed to have been having an affair with. They announced their separation in 1992 and eventually divorced in 1996, a year before her death. Here's the letter in full:

"Dearest Erika,

"I have received your letter and of course read it with concern and a wish to support you in any way I can.

"There is a great deal of pain inside you, hence the block as you call it - that is a natural response for someone who has been through the traumas you've experienced.

"Reading between the lines of your letter I feel a very special lady is struggling with a low self-esteem because of all the bruises you had to deal with, mentally and physically.

"I do know that it takes great courage to write as you did and with that honesty and clarity the light will appear in your tunnel.

"I am thinking of you so much, hang on in there Erika.

"Lots of love from Diana x."

Diana is known to have struggled with her self esteem during her marriage and developed an eating disorder. The letter, which is due to go up for sale at Julien's Auctions in LA, is expected to fetch £4,000. "Our understanding is that Erika was a member of the public who was experiencing a troubled time and she wrote to Diana for advice and support as she herself had experienced a difficult time with the break up of her marriage," Martin Nolan of the auction house said.