Jessica Simpson marked the success of her new book and a successful book tour with a heartfelt message on her Instagram.

Simpson’s memoir, “Open Book,” was released on Feb. 2 and she’s been going across the country promoting it ever since. The singer, 39, talks about the most intimate moments in her life, including her marriage to Nick Lachey, sexual abuse she experienced during her childhood, backlash to her wardrobe early in her career, turning down “The Notebook” and the pressure she felt to lose weight, which led her to use diet pills.

The star took to Instagram on Sunday to share a note about the book’s success.

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“This is me singing “Hallelujah” down the hall after finding out my truth not only set me free, but set the lives of so many readers and listeners of ‘Open Book’ free,” she wrote over a black-and-white image of herself belting out the song in what appears to be a hotel hallway.

She continued: “Meeting thousands and thousands of you these past 2 weeks has given purpose to my life all over again. My smile was real, my hugs were true, and these memories I will hold so close to my heart forever.”

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The "I Wanna Love You Forever" singer then thanked fans for propelling her book to the top of the New York Times Best Seller list in the category of combined print and e-book nonfiction.

“Thank y’all for helping my bravery break unexpected records and giving me the chance to be heard as a #1 BEST SELLING AUTHOR!!!” she wrote. “This is a moment for all of us to share, always and forever, your best friend...Jess.”

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The star has been posting countless shots to her Instagram promoting both her book and documenting her romp around the country to promote it. Earlier this month, she shared an image of herself at a newsstand in Hudson where she was so excited to see her own book that she actually purchased a copy.