Jessica Simpson's children are in "awe" of the success of her memoir.

Jessica Simpson

Jessica Simpson

The 39-year-old singer - who has kids Maxwell, seven, Ace, six, and Birdie, 11 months, with her husband Eric Johnson - is thrilled that she's been able to share the success of 'Open Book' with her children.

She told E! News: "I'm so proud to share this moment with my family, with my children. They're so excited, they're so in awe. 'Oh, that's what mommy was doing when she says she's writing a book.'

"Max was like, 'You wrote a chapter book, mom.' It's just so cute, they're really proud of me. That pride that my children have of me, there is no better accomplishment."

Jessica revealed her kids have actually read "some parts" of her book.

And the blonde beauty - who was married to actor Nick Lachey from 2002 until 2006 - is proud of herself for being so open and honest in the memoir.

She reflected: "I'm so proud of myself for sharing these experiences. It's one of those things where it's all out there, I have nothing to hide, I'm not ashamed of anything.

"In my mistakes, now, I can own them, lead with them and show that I am not perfect and I don't want to be perfect."

Jessica also admitted to being surprised by the impact of 'Open Book'.

She confessed to being shocked by just how many of her fans have related to her story.

The singer - who has been married to Eric since 2014 - said: "I didn't realise how much this book would actually speak to people because, you know, I'm just opening up about myself, my mistakes and choices. There's so many moments in the book that relate to so many different people."