Paul McCartney is bringing “Grandude” back.

The Beatle is writing a sequel to his children’s book Hey Grandude!, Rolling Stone reports. The original book, published in 2019, followed a group of children hanging out with their grandfather and his mysterious compass. A reviewer for Kirkus praised the book, writing, “Readers will roll up for repeats, and not just because of the name on the cover.”

The sequel, titled Grandude’s Green Submarine, introduces a new character, Nandude, who rescues Grandude and his young crew when they find themselves in a tight spot.

On a webpage for the book, publisher Random House Children’s Books writes, “This tale is perfect for little explorers and Paul McCartney fans alike! Artist Kathryn Durst returns with glorious, humor-filled illustrations that are as beautiful as ever.”

“I’m really happy with how Hey Grandude! was received, as this was a very personal story for me, celebrating Grandudes everywhere and their relationships and adventures with their grandchildren,” McCartney said in a statement. “I love that it has become a book read to grandkids at bedtime all around the world. I always said if people liked the first book and there was an appetite for more, I would write some further adventures for Grandude—so he’s back and this time with his special invention, Grandude’s green submarine!”

Grandude’s Green Submarine is slated for publication on Sept. 2.

Michael Schaub is a Texas-based journalist and regular contributor to NPR.