Britney Spears has landed a “record-breaking” publishing deal for a tell-all memoir about her rise to fame, her relationship with her family and her experience living under a conservatorship for more than a decade.

Page Six reported on Monday that publisher Simon & Schuster had secured the deal for the pop star’s memoir for as much as US$15m (£11m, A$20.8m) after a massive bidding war involving multiple publishers.

An unnamed source told Page Six that “the deal is one of the biggest of all time, behind the Obamas”. The president and first lady signed a deal worth an estimated US$65m to write multiple books for Penguin Random House in 2017.

The deal comes months after Spears successfully fought a court-ordered conservatorship, which had been put in place by her father, Jamie Spears, for almost 14 years. The conservatorship, typically for older or infirm people who can no longer make decisions for themselves, was instigated in 2007 after a period of mental illness for Spears. Rumours spread that the singer was being held in the conservatorship against her will, which lead to the creation of the #FreeBritney movement.

In 2021 Spears gave public testimony about the conservatorship for the first time, telling a Los Angeles judge that she had been forced to work by conservators despite begging for breaks, and that she had no control over her finances, was denied her wish to marry her boyfriend, and was barred from removing her birth control despite her wish to have a third child.

“I’ve been in shock. I am traumatised,” Spears said. “I just want my life back.”

The judge suspended her father from the conservatorship in September, before it was lifted entirely in November. Spears said soon after that she believed her family members “should all be in jail” for the “demoralising and degrading” treatment she says she experienced under the arrangement.

Spears recently publicly condemned her sister, Jamie Lynn, who made allegations about the singer’s mental health while promoting her own memoir on Good Morning America.

Jamie Lynn alleged in the interview last month that Spears had once locked them both in a room while holding a knife and described her behaviour over the years as “erratic, paranoid and spiralling”.

In response, Spears accused her sister of “sell[ing] a book at my expense”. Her lawyer issued a strongly worded cease-and-desist to Jamie Lynn, asserting that Spears would “no longer be bullied” by her family.

“Although Britney has not read and does not intend to read your book, she and millions of her fans were shocked to see how you have exploited her for monetary gain. She will not tolerate it, nor should she,” the letter read.

Last week, Spears was invited to US Congress to discuss her conservatorship legal battle, with two members of the House of Representatives writing to her to ask her to speak about her “empowering” story and “the emotional and financial turmoil you faced within the conservatorship system”.

… we have a small favour to ask. Millions are turning to the Guardian for open, independent, quality news every day, and readers in 180 countries around the world now support us financially.

We believe everyone deserves access to information that’s grounded in science and truth, and analysis rooted in authority and integrity. That’s why we made a different choice: to keep our reporting open for all readers, regardless of where they live or what they can afford to pay. This means more people can be better informed, united, and inspired to take meaningful action.

In these perilous times, a truth-seeking global news organisation like the Guardian is essential. We have no shareholders or billionaire owner, meaning our journalism is free from commercial and political influence – this makes us different. When it’s never been more important, our independence allows us to fearlessly investigate, challenge and expose those in power.