Britney Spears to pen $22 million memoir in 'one of the biggest book deals of all time'

Britney Spears has landed a book deal said to be worth as much as US$15 million ($22m).

Insiders say the pop star, 40, has reached a deal with publishing house Simon & Schuster to release her tell-all memoir about her life, family and career, according to the New York Post.

The landmark deal comes after several publishers engaged in a bidding war over her book. Publishing insiders say the deal is "one of the biggest of all time, behind the Obamas".

The rights to Barack and Michelle Obama's books were sold in 2017 for a figure reportedly over US$60m ($89m), the largest ever known sum for nonfiction books.

The singer has been hinting she will pen her own memoir after she responded to the claims made in her younger sister Jamie Lynn Spears's revealing book Things I Should Have Said, released in January this year.

At the time, Britney wrote on Instagram: "Congrats best seller…..The nerve of you to sell a book now and talk s*** but your f***ing lying…..I wish you would take a lie detector test so all these masses of people see you're lying through your teeth about me !!!! I wish the almighty, Lord would could come down and show this whole world that you're lying and making money off of me !!!! You are scum, Jamie Lynn."

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And Britney's lawyer Mathew Rosengart sent a strongly worded cease-and-desist to her sister, saying his client would no longer be "bullied" by her family members.

"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.

The singer's infamous conservatorship ended in November after 13 years. Since then, she has been the subject of several documentaries focusing on her legal battle for freedom, some of which she has criticised.

Britney recently hinted that she was ready to start writing her own version of events, sharing a photo of an old-school typewriter on her Instagram and writing: "Shall I start from THE BEGINNING???" [sic].

Earlier this month, the pop star teased that she might be working on new music for the first time in five years. She shared a video of herself dancing on Instagram, writing in the caption: "This is a tease of what's to come".