Diana wrote a heartfelt note to a struggling fan. Photo / Getty Images
A heartfelt letter Princess Diana wrote to a distressed woman battling low self-esteem has been unearthed after more than 20 years.
Diana appeared to draw on her own experience of "trauma" caused by the breakdown of her marriage to Prince Charles when she penned the letter, according to the Daily Mail.
Writing in response to a note from a fan who was struggling to cope, the late princess wrote: "I know that it takes great courage to write as you did."
Diana also recognised the "mental and physical bruises" the woman had to deal with.
The princess wrote the letter just days after her 1995 Panorama interview with Martin Bashir was aired in which she candidly discussed her failed marriage in unprecedented detail.
"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 had experienced years of low self-esteem during her unhappy marriage with Charles that led to her to develop an eating disorder.
The letter was acquired from Erika by a British Royal collector who has now consigned it for sale with American-based Julien's Auctions. It is tipped to sell for ($7,793) £4,000.
Martin Nolan, of Julien's Auctions, said: "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.
"Diana is very gracious and compassionate, and she offers great encouragement to Erika that there will be light at the end of the tunnel.
"It seems as if she is speaking from her own personal experience when she writes this.
"Diana would write letters to troubled people and one can imagine how much it would have meant to Erika to receive such a warm response."
Diana and Charles' marriage was known to have been under strain for several years, with Diana openly discussing her unhappiness, before they eventually divorced in 1996.
She was romantically involved with Dodi Al Fayed when the couple and their driver Henri Paul died in a car crash in Paris on August 31, 1997.