Random House boasts the book, which features illustrations by Kathryn Durst (no relation to Robert or Fred), has an exceptionally effective "wind-down-to-bedtime ending."
The book follows the adventures of a magical grandpa, the eponymous Grandude, and his four grandchildren, who he calls his "Chillers". Grandude is an "elderly, magical gentleman," according to The Guardian.
The singer-songwriter recently claimed his first number one album on the US Billboard chart for 36 years with his latest record Egypt Station.
McCartney is the latest in a line of musicians to venture in to children’s publishing, with fellow former Beatle Ringo Starr and Rolling Stone Keith Richards also having released picture books with varying degrees of success.
The picture book is set to be illustrated by Kathryn Durst, who said she was "thrilled" to work on the project. "I have wonderful childhood memories of my dad taking my siblings and me on exciting adventures, just like Grandude does in the book."
McCartney selected Durst’s work based on samples he’d been given by her agent in England. She was up against about 10 other artists. Initially, Durst didn’t think she landed the job. She’d sketched the drawings in November and it was six months before she got the news. And then she was told she couldn’t tell anyone.
"We both want to make an exciting and beautiful book that kids will want to read again and again!", said Kathryn.
The book will be published in hardcover under the Puffin imprint in the UK and the Random House Books for Young Readers imprint in the US.
"I wanted to write it for grandparents around the world so they can have something to read to the grandchildren before going to sleep," said the musician.
Title illustration: Paul McCartney with his book 'Hey Dude', 2018.