Rowling, 56, has posted a picture of a crafty confection she has woken up to on the day of its release.
One image shows a book-shaped slab of Chocolate wrapped in the cover of her novel, balanced on a glass tray covered in chocolate sprinkles.
Another image shows the inside of the “book”, with “Happy Publication Day” written inside and five small confections beside it.
Rowling tweeted the images today with the caption: “Woke up to a chocolate book, which I think you’ll agree is a very nice way to wake up.”
The book tells the tale of Jack, a young boy who loves his childhood toy, a pig that is aptly named Dur Pig.
Dur Pig gets lost on Christmas Eve, and in a Christmas miracle his replacement toy, the Christmas pig, comes to life.
The pair set off on a festive adventure in an attempt to find and rescue Dur Pig and save Jack’s Christmas.
The tweet now has over 6000 likes, with over 150 people commenting on the novelty novel.
@AidenWells19 said: “ Oh, that’s rather lovely. Does it taste as good as it looks?”
@yrhenwrach commented: “I don’t think it gets much better than that! Happy publication day!”
@floatingstarfis replied: “That is indeed a wonderful way to wake up in the morning! Happy publication day.”
@SlimWiggy added: “Oh, that does look lovely! If only we could order this edition…”
Rowling revealed recently that her son David’s favourite toy when he was little was a pig.
Due to the regularity with which the pig went missing, Rowling bought a replacement one and kept it in a cupboard, leading to the idea for her new book.