Paul McCartney Takes on New Adventures in Picture Book Sequel 'Grandude's Green Submarine'

Grandude is back for more adventure!

Two years after the release of Paul McCartney's first picture book, Hey Grandude!, the 79-year-old musician has dropped the sequel to the beloved story, Grandude's Green Submarine.

The children's book, out Tuesday, follows Grandude — who was inspired by a nickname McCartney's own eight grandchildren gave him, and his grandchildren (or "Chillers" as McCartney calls them) as they set off on a journey to find their music-loving grandmother, Nandude.

"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," the music icon said in a statement. "I love that it has become a book read to grandkids at bedtime all around the world."

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"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!" McCartney added.

Canadian artist Kathryn Durst, who also did the artwork for McCartney's first picture book, said she is "thrilled" to collaborate again with the Beatles musician on the second installment of the Grandude series.

"I think this is the adventure book we all need during this time, when everyone is stuck at home and longing to travel to exciting new places," she said in a statement. "I really enjoyed drawing the newest character in the book, Nandude, particularly because we both share a love of playing the accordion!"

Grandude's Green Submarine, published under the Random House Books for Young Readers imprint, is available to read now.