If the rumours are to be believed, it would be bigger than Spare. The ultimate first-hand account, not merely a publishing phenomenon but an extended multi-platform event including interviews, streaming components and global rights deals.
Meghan Markle's autobiography. For years it has been talked about as a potential project, never fully confirmed.
Indeed, buried right at the end of a Vanity Fair piece on the Sussexes last year was a reported rumour that Meghan's team had quietly floated the concept of a post-Harry divorce book to publishers.
The conversations (and, yes, supposedly, there were conversations!) were intended to gauge publisher interest in a hypothetical tell-all in the event of a future split.
Vanity Fair was quick to say that it was all purely exploratory (no manuscript, written proposals or offers) and any discussion was just to assess the appetite for such a memoir.
The appetite would surely be huge, and - given that Prince Harry received a reported £16 million in advance for his autobiography - so would the financial offers!
'She has been documenting everything since before Megxit.'
After all, neither she nor Harry has ever really gone into detail about some of their most damaging claims against the Royal Family, or who or what made Meghan feel suicidal and how she feels about it all now.
But it's widely believed Meghan keeps a diary and detailed records.
According to one publishing insider, 'Voice notes on her phone at 1am. Written journals. Structured reflections. She has been documenting everything since before Megxit.'
Its release would surely be bigger than Harry's Spare, which became the fastest selling non-fiction book of all-time, shifting more than 1.4 million copies on its first day of release in January 2023. By the following year, sales were in excess of six million. Publishing experts say Meghan's book could surpass even those numbers.
Although presumably a Meghan memoir would explore her life prior to joining the Firm - growing up as a child of divorce, struggling to make it in Hollywood before winning the part of Rachel Zane in Suits - it would of course be the past 10 years, since her relationship with Harry became public, that would generate the most headlines.
We already know from the couple's Netflix documentary how deeply hurt Meghan felt by the way she claims she was treated by Harry's family, by the press and by her own father.
Meghan also has a network of powerful Californian friends upon whom to call.
Neighbour Oprah Winfrey was the first to help Meghan and Harry tell their 'truth' on primetime TV - prompting that genius line from the late Queen Elizabeth that 'recollections may vary'.
Watched by 17 million Americans, 11 million Brits and millions more worldwide, the CBS interview in March 2021 was a global cultural event.
Meghan also counts Mellody Hobson as a mentor. Co-chief executive of Ariel Investments and former chair of Starbucks, the 57-year-old is married to Star Wars film-maker George Lucas and is a stellar networker in the world of finance and media. Such is her influence, she can open just about any door in Hollywood.
Another influential pal is Nicole Avant, a former diplomat who is married to the Netflix co-CEO Ted Sarandos.
Although the Netflix relationship has cooled - the Sussexes' five-year £74 million deal was only extended in a non-exclusive arrangement and the streamer pulled out of Meghan's As Ever lifestyle business - the personal relationships are still good.
Nicole, 58, has reportedly long been an advocate for Meghan - particularly behind the scenes in the notoriously tricky la-la land of Hollywood.
It's she who is thought to have fostered conversations about how a potential Meghan memoir could be developed in partnership with Netflix.
'A risk... and a leverage'
Meghan reportedly sees the book as an opportunity for a reset, and she would like to highlight what she sees as her success in America, as well as tell her version of events.
But the timing is risky.
Harry is desperately trying to mend his relationship with his father King Charles, and a new Meghan memoir could derail that. Thus, any publication is not believed to be imminent.
Harry wants to stabilise and improve relations with the Royal Family and is said to be pleased that Archie, seven, and Lili, five, have occasional chats and video calls with their grandfather.
So Meghan knows a book is a risk - but it's also leverage.
You can bet your bottom dollar that much of her memoir is already written. It's really just a question of when she'll decide to publish...
This feature first appeared in Woman magazine. Subscribe now and get your first 6 issues for £1.