One of Farrah Fawcett's closest friends, Alana Stewart, is publishing a diary she kept as the actress battled cancer for three years and then died last month.
Publisher William Morrow, an imprint of HarperCollins, says "My Journey With Farrah: A Story of Life, Love and Friendship" will be released Aug. 11. The book is thought to be the first insider's look at Fawcett's illness.
Stewart, the ex-wife of rocker Rod Stewart and a friend of Fawcett's for 30 years, said she was encouraged to go into print by Fawcett herself and by Ryan O'Neal, the "Love Story" movie star who was Fawcett's long time companion.
"Farrah had originally encouraged me to write this book. It was her idea. However, while I was contemplating my decision, her health took a turn for the worse, and I could no longer seek her advice," Stewart said in a statement.
"So I turned to Ryan O'Neal. He was so positive and so supportive. 'You have to do it', he said emphatically. 'There will be lots of people writing books about her. Yours will be the truth, and it will be a wonderful tribute to her. You have to do it!' " she said.
Some of the proceeds will be donated to the Farrah Fawcett Foundation for cancer research.
Fawcett told her own story in a heart-wrenching video diary of her last three years that was broadcast on U.S. television in May as the actress entered the final few weeks of her life in seclusion at her Los Angeles home.
Fawcett, the pinup icon and "Charlie's Angels" star, died June 25 at age 62. Stewart, an actress and former wife of rock star Rod Stewart, has appeared in such films as "Swing Shift" and "Funny Lady."
The Associated Press and Reuters contributed to this report.