"It's one of those things -- before you have a kid, you either don't want to have a kid or you do want to have a kid or you don't know, and then it just happens to you. And you're never ready for it, and it's always gonna teach you and is still teaching me," Tatum said about fatherhood, which he noted in the book is his favorite role to date.
He continued, "My little is around here and like, day to day, you know that you're not gonna be the coolest kid in the room, and she's gonna keep you in line."
Tatum said his daughter, who he shares with ex-wife Jenna Dewan, challenges him more creatively on daily basis than he's ever been challenged in his life.
"I don't know what it's like to have a son, but I know what it's like to have a daughter, and it is wild," The Lost City actor shared. "I've never been creatively challenged more in my career or in my life than just being a dad, simply, day to day."
While the first book in the Sparkella series told the story of the titular character's first day at a new school, the second sees Sparkella attempting to create the perfect castle for her sleepover with her new friend, Tam. A frustrated Sparkella worries her castle will never be finished in time, but with some help from her dad, she not only learns an important lesson of patience, but how to figure out creative new ways to do things when your original plan falls through.
The book's trial and error lesson was actually inspired by a special day that Tatum shared with his daughter, during which the pair built a birdhouse.
"It was one of those random days -- we don't do a ton of very cliché projects. We make a lot of things -- we paint, we draw murals. We do all kinds of things that are creative, but we never made something so cliché as a birdhouse," Tatum explained.
He continued, "I remember like, when she came and just had the idea and I was like, 'Oh no.' I was like, 'Ok, she's already got the idea of how she wants it to look, how she wants it to be painted, the levels, how she wants it to hang."
The project seemed nearly impossible for the pair, but knowing how strong-willed his daughter is, Tatum was determined to turn her version to reality -- or as close to reality as he could get.
"I knew about, at least 70 percent of what she wanted to do wasn't gonna work or we didn't have the materials, and I was just like, 'Oh man, this is gonna be a day,' 'cause she's very, very strong-willed," Tatum said. "And I remember not having the tools to know how to tell her that this wasn't gonna really be exactly how she wants it to be. So, I just kinda had to let her fail."
The process wasn't easy. Like building Sparkella's castle, creating Everly's dream birdhouse came with plenty of frustration and lots of patience, but at the end of it all, it turned out to be one of "the cooler birdhouses" Tatum said he's ever seen.
"It was a long process. Lots of frustration. Lots of patience, and what we got to, was one of the cooler birdhouses that I've ever seen," the proud dad gushed. "I don't know if birds really want to live in it, but we really, really like it. We haven't actually hung it in a tree yet, and we don't actually know if it's functional, but we both really love the birdhouse."
What Tatum said both he and Everly learned, was how to "go on the journey," no matter the outcome.
"What we both learned, is just how to be with each other inside of something we both want to have happen and just go on the journey," Tatum added.
The One and Only Sparkella and The One and Only Sparkella Makes a Plan are both available now in hardcover and on audiobook, wherever books are sold.