Demi Moore isn't "sitting around feeling sorry for herself."

The 49-year-old actress has been battling personal problems since she split from Ashton Kutcher last year, after he allegedly cheated on their wedding anniversary.

Following the breakup, Demi was hospitalised for exhaustion and reported substance abuse.

Demi signed a contract with a book publisher to write a memoir and the star is not holding anything back about her personal life in the manuscript.

"Demi kept a detailed diary throughout her marriage to Ashton, and she's putting those journals together," a source told Star magazine.

"Everyone thinks she's sitting around feeling sorry for herself, but the truth is that she's been busy writing!

"Ashton is not going to be happy about what Demi has to say, but she doesn't care. She is going to open up about all his other women and his betrayals."

Demi wants to triumph over her troubled past. She is battling her demons head-on.

"Her therapists and recovery sponsors convinced her that she needs to face her past in order to conquer it and move on," the source explained.

"Plus, she feels so victimised by all the rumours floating around. She wants to set the record straight."