Kelly Clarkson Wrote a Song for Hoda Kotb's New Book, Inspired by Daughter Haley

Hoda Kotb just published her first children’s book, I’ve Loved You Since Forever, and the title has a very special meaning for the Today co-host.

“As I was waiting and hoping and wishing for Haley, when I started to believe that maybe I could be a mom too, maybe I didn’t miss my window, maybe there’s still hope here … It was that kind of revival,” Kotb tells PEOPLE exclusively in this week’s issue.

“I was scribbling in my journal and waiting to see if it would come to pass and I could feel that child. I felt like they were sleeping under the same moon and stars,” she continues.

“Somewhere out there this child is there for me and that phrase, ‘I’ve loved you since forever,’ was something that I had written down because that’s what it felt like.”

After a battle with breast cancer a decade ago left her unable to have a child, Kotb adopted daughter Haley Joy, born Feb. 14, 2017.

“Sometimes you can love someone before you’ve met them,” the new mom says. “You just know. I feel like this book, that’s kind of where it started.”

Once Kotb wrote her book, she asked pal Kelly Clarkson to turn her words into music. “My heart exploded,” Kotb says after hearing the song for the first time. (The song will premiere on Today Thursday).

“Kelly is an unbelievable human being. She changed my life. This song is now part of our family history. It’s amazing that she did that for Haley and for me and for anyone that listens to it and feels like the song is about them.”

Kotb’s book, I’ve Loved You Since Forever, is available Tuesday.

For more on Hoda Kotb and Kelly Clarkson, pick up the latest issue of PEOPLE, on newsstands Friday.