The big reveal in The Princess Diarist is that Carrie Fisher (Princess Leia) had an affair with Harrison Ford (Han Solo) during the making of the first Star Wars film. But The Princess Diarist still manages to be about quite a bit more than that.
Fisher's comedic talents are on show in this witty and meandering memoir, as she turns a gimlet eye on her own early success, on fame, Hollywood and the phenomenon Star Wars became.
Although still largely defined by her Princess Leia debut (and by the infamous metallic bikini she wore in Return of the Jedi while enslaved by Jabba the Hutt), Fisher is the author of an autobiography, Wishful Drinking, and several novels, including Postcards from the Edge, which took a look at Hollywood's dark side and was later made into a film starring Meryl Streep and Shirley MacLaine.
She has talked about her diagnosis with bipolar disorder, her drug addiction and bouts of electroconvulsive shock therapy.
So it would be wrong to expect her to play things straight in The Princess Diarist - and she doesn't.
Darkness abounds, whether it's in a joke about waterboarding or a reference to the weed-induced paranoia brought about by "the brutal strength of Harrison's preferred strain of pot," or a dig at the industry's sexism: "As you no doubt are aware, if you have a penis and a job, being handsome is a fantastic bonus but hardly a necessity."
As for the affair, she lays it out frankly early on. "I've spent so many years not telling the story of Harrison and me having an affair on the first Star Wars movie that it's difficult to know exactly how to tell it now," she writes.
"Harrison's been very good about not talking about his half of the story," she goes on. "But just because he's been good doesn't mean that I have to continue to be."
He was married; she was young and insecure, a fact the diaries poignantly emphasise, laying bare a 19-year-old's dreams and worries about her lover.
The diary section - actual excerpts from her diaries at the time - is raw and heartbroken, and a bit too long: Fisher's older self, looking back on events is more charming than her angst-ridden younger version going through them.
Ford comes across as an emotionless creature, and they rarely talked about anything serious. Despite its impact on her, Fisher says their relationship was "a very long one-night stand."
The Princess Diarist is, like Fisher's other work, a statement about the price of fame and the challenges it poses, especially for women.
One of the big inequalities of Hollywood is the issue with women's age, a debate that flared again with The Force Awakens last year when social media trolls attacked her appearance.
On Twitter she replied, "Please stop debating about whether or not I aged well. unfortunately it hurts all 3 of my feelings."
It's not as though this is something she hasn't come across before. Fisher tells how, at a signing in the US, a father introduced his daughter to her, only to have the little girl whimper and ask for "the other Leia, not the old one."
The father was embarrassed, but, "It all ended well," she writes, "with me promising to get plastic surgery … and getting her father to promise to read his daughter bits of Wishful Drinking, and look at its pictures together, so she'd see what the actual Carrie was like and how pretty she could be once the endlessly extraordinary Leia was finished."
Fisher clearly has mixed feelings about Princess Leia, Star Wars, Hollywood and her fans. But she also kind of loves them - and they've allowed her to pay her bills. This weary, contrarian whimsical memoir is a testament to that ambivalence.