ForMatthew McConaughey, inspiration for his debut children’s book hit in the middle of the night. In a dream. In song.

“It came to me at 2:30 a.m. as a ditty in a dream,” the actor, 53, tells PEOPLE of what would becomeJust Because, out Sept. 12.

“It was a song in my mind, and I got up and wrote it down.”

Aspirited collection of life lessonsand conundrums untangled in rhythmic couplets, the picture book sparked “a lot of good conversations” withhis kids Levi, 15, Vida, 13, and Livingston, 10,wife Camila, and even hisever-discerning mother Kay, he says.

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matthew mcconaughey just because 2023 children’s book.Penguin Young Readers

Just Because Matthew Mcconaughey book

Penguin Young Readers

“My mom’s 91 and she said, ‘That’s not just for kids. You even reminded me of some things in there.'”

The Oscar winner, whose2020 memoirGreenlightsbecame a bestseller, says he hadn’t consciously set out to write a children’s book.

“Just being a dad, I mean, you’re thinking about your kids all the time [and] I think that afternoon, I’d been having conversations with my children about certain new things that they were crossing for the first time or, ‘Well, this happened and I’m not sure how to feel about it. And I wanted to do this, but I felt I needed to do this, and I was confused,’ " he says.

AUSTIN, TEXAS - APRIL 27: (L - R) Camila Alves McConaughey, Matthew McConaughey and Levi Alves McConaughey attend the 2023 Mack, Jack & McConaughey Gala at ACL Live on April 27, 2023 in Austin, Texas.Gary Miller/WireImage

matthew-mcconaughey-book0918

Gary Miller/WireImage

“Evidently it was in my subconscious… Once I knocked all the couplets down in the rhythm, it sort of wrote itself.”

McConaughey valued feedback from his kids about all aspects of the book.

One of the couplets that resonated, he says, was “Just because you’re wailing, doesn’t mean you’re a crier. Just because you lied, doesn’t mean you’re a liar.”

an inside page from Matthew McConaughey’s Just Because book.Renée Kurilla/Penguin Young Readers

Just Because-inside0918

Renée Kurilla/Penguin Young Readers

“We talked about that one quite a bit because my kids have seen it,” McConaughey says. “We do it all the time: We label somebody. Somebody fibs to you: ‘Oh, you’re a liar.’ Well, that’s a big blanket to put on somebody. If you call someone a liar, they get defensive: ‘Whoa, my whole being? You mean I’m all about untruths?’ But if you say, ‘No, that was a lie,’ that person has the choice now to go, ‘I know, I’m sorry about that.'”

Ultimately, he hopesJust Becauseis a relatable conversation-starter for families and “speaks to the kid in all of us.”

For more from McConaughey, pick up this week’s issue of PEOPLE, on stands Friday.

source: people.com