Britney Spears memoir reaches bestseller status a week before it hits shelves

Singer Britney Spears arrives at Wango Tango 2013 at The Home Depot Center on May 11, 2013 in Carson, Calif. Dan Steinberg/Dan Steinberg/Invision/AP hide caption

toggle caption Dan Steinberg/Dan Steinberg/Invision/AP

Singer Britney Spears arrives at Wango Tango 2013 at The Home Depot Center on May 11, 2013 in Carson, Calif.

Dan Steinberg/Dan Steinberg/Invision/AP

Pop star Britney Spears' new tell-all book, , doesn't come out until next week — but it's already at the top of Amazon's Best Seller's list.

New excerpts released by magazine are drawing fans interested in her side of the story. And her Instagram, where she's usually showing off her dance moves, is now seeing Spears in book-selling mode. In an ad she posted, she says: "I'll have a good book one day. A good mysterious book."

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