Channing Tatum on Daughter Everly Turning 10 and How She Inspired New 'Sparkella' Book (Exclusive)

The actor and children's book author opened up to ET about his little girl's milestone birthday.

Channing Tatum is turning to his miniature muse for inspiration. The actor and children's book author is opening up about how his daughter helped him with his latest installment in his Sparkella book series.

Recently, Tatum spoke with ET's Rachel Smith and reflected on his new book, The One and Only Sparkella and the Big Lie, which is the third book in his best-selling series, and explained how this book is really "different than the first two."

"The first two kind of connected on some level," he explained. "The first one was about sort of the anxiety of expectations of a new place and then this second one was really about when your expectations are completely failing... and what do you do to try to make the best of it? This one's kind of just a complete departure."

Tatum explained how he spoke with some teachers and experts and one thing that seemed to come up a lot was about the anxiety that comes when young kids first start understanding the concept of lying and storytelling.

"They're kind of figuring out what that means and it makes them feel and is it OK? What’s the difference between make-believe and then a lie?" he added.

For Tatum, a memory of his daughter, Everly, telling her first "big, yucky-feeling lie" helped inform the story quite a bit.

"She stole a little toy car from school, and she was just sick about it," Tatum recalled, explaining how Everly is "a hustler" who always convinces him to come back into her room at night to read more stories, because she doesn't want to go to sleep.

"[One night], she kept calling me back in. I could tell something was a little different with this, but I thought she was just hustling me. And then, all of a sudden, just like full tears," he shared. "She was like, 'I need to tell you something, but I'm afraid and I'm gonna get kicked out of school and you’re gonna call the police.' And it was just like a whole fear spiral."

"You could tell she was just living with it for weeks and it was just making her sick," he added. "Then once she told me, I obviously had to tell her, I was like, 'Look, you’re not gonna be in trouble as long as you tell me the truth. It's OK, I’m not gonna call the police, you’re gonna be fine.' Then she told me and I could just see the whole weight lift off of her."

But Everly -- whom Tatum shares with ex-wife Jenna Dewan -- is more than just a source of inspiration. She also helps more directly with the art for the book as well.

"She doesn't really get to know the stories until I write them," Tatum explained. "We kind of want that to be, like, a surprise for her."

Everly is about to turn 10 on Wednesday and Tatum said they celebrated a little bit ahead of time, sharing, "We just went to Six Flags, so we kind of did it early... [but] she's got a big birthday coming up this coming weekend, so it's fun."

With Everly in double digits, it's only a few years before he'll be the dad of a teenager, and Tatum fully admitted he wasn't quite prepared for that, emotionally.

"I don't think anybody's ready for the teenage years," he said with a laugh. "I heard it's like aliens coming down and they just snatch your kid away and then bring them back around 22 or so!"

Tatum's new book, The One and Only Sparkella and the Big Lie, is out now.