HarperCollins announced on Wednesday that the "Charlie's Angels" star has an agreement to create a book that will offer advice to young women about health, fitness, nutrition and general well-being.
The company says Diaz wants to "engage and empower" women.
The book, which is currently untitled, is scheduled for publication in the fall of 2013.
Diaz, who turns 40 later this month, has spoken often about the importance of health and fitness and her desire to share advice.
The Associated Press contributed to this report.