PARIS (AFP) - Two years after escaping her father's guardianship, Britney Spears recounts her years as a superstar who became a victim of her success in a highly anticipated memoir being published on Tuesday.

One revelation from "The Woman in Me" has already made headlines: with Spears saying she felt pressured into having an abortion while dating fellow popstar Justin Timberlake between 1999 and 2002.

"If it had been left up to me alone, I never would have done it," she writes. "It's one of the most agonizing things I have ever experienced in my life."

The publishers have kept a tight lid on most of the contents -- unsurprising since Simon & Schuster reportedly paid more than 15 million dollars for the rights.

It was not a risky bet, however -- the book is already topping the pre-sale chart at Amazon US. It is being released on Tuesday in around 20 countries and 10 languages.

"Reliving everything has been exciting, heart-wrenching, and emotional, to say the least," Spears told People magazine.

The emotional turmoil means the 41-year-old singer has only recorded a small section for the audiobook, leaving the rest to actress Michelle Williams.

"There are so many hard things to read in the news about my book," she wrote on her Instagram this week.

"Then I woke up this morning and said it's all relative... nothing really matters at this point."

Up and down

Spears came from a very humble background and found early fame on "The Mickey Mouse Club" alongside other future stars Ryan Gosling and Christina Aguilera.

At 16, she became one of the most famous women on the planet with 1998's iconic "...Baby One More Time", which sold 10 million copies to become one of the biggest hits of all time.

Eight more albums followed, often selling in the millions, including "Oops!...I Did it Again" and "In the Zone", combined with spectacular world tours.

Growing up in the media glare, relentlessly sexualised by her marketing from a young age, Spears lost her footing in 2007.

A highly public breakdown in which she shaved her head and was filmed attacking a paparazzi's car led to her father, Jamie Spears, taking legal control over her life.

It meant he controlled her finances, career decisions and even whether she could see her children or marry -- which Spears described as tantamount to "abuse".

Her fans organised a campaign -- #FreeBritney -- aided by media investigations that finally led a court to remove her father as guardian in September 2021.

She apparently no longer speaks to her family.

Her life has hardly been smooth sailing since then -- her marriage to model Sam Asghari ended in August after just 14 months.

But Spears at least looks set to add a number one bestselling book to her list of artistic accomplishments.