Prince Harry hopes the "truth" will help heal his ongoing rift with his family.
In a teaser for the interview released Thursday, Harry appears to share his motivations for writing the book.
"Ultimately, I don't think we can ever have peace with my family unless the truth is out there," he says.
Harry is also asked to explain why he refers to his brother, Prince William, as his "beloved brother" and "arch-nemesis" in the memoir.
Spare will explore Harry's life, from the death of his mother in 1997 to the present day."With its raw, unflinching honesty, Spare is a landmark publication full of insight, revelation, self-examination, and hard-won wisdom about the eternal power of love over grief," an official description reads.
The book will be released Tuesday, Jan. 10.
The couple addressed their exit and some of their issues with the royal family and British press in the Netflix docuseries Harry & Meghan.
Harry said in a preview for an interview with Anderson Cooper for 60 Minutes set to air Sunday that there has been "absolutely no willingness to reconcile" on the part of his father, King Charles, or brother, William.
