It is the second official update on life in the wizarding world since the events depicted in Harry Potter and the Deathly Hallows. The first came earlier this year, in the form of a characteristically acid-tongued despatch from the Quidditch World Cup by nosy newshound Rita Skeeter.
And now fans are set to rejoice again at the latest offering, which gives readers the lowdown on one of the sagas most despised villains - former Defence Against the Dark Arts teacher and aspiring tyrant Dolores Umbridge.
The 1,100 biography tells how Umbridge rose through the Ministry of Magic, crushing anyone who stood in her way and shocking colleagues with her extreme views on blood purity - despite being half-Muggle (non-magic) herself.
To anyone familiar with the books, the news that Umbridge's rise to the top was the result of her vindictive scheming won't come as much of a surprise. The real delight is that J.K follows the biography with her own thoughts on the character, including her real-life inspiration.
"Once, long ago, I took instruction in a certain skill or subject (I am being vague as vague can be, for reasons that are about to become obvious), and in doing so, came into contact with a teacher or instructor whom I disliked intensely on sight.
"The woman in question returned my antipathy with interest," she writes, mentioning that although the similarities were 'grossly exaggerated', she had been inspired by the hated teacher's love of all thing frilly and childish.
"I have noticed more than once in life that a taste for the ineffably twee can go hand-in-hand with a distinctly uncharitable outlook on the world," J.K observes wryly, describing how she had given this particular trait to Umbridge.
Pottermore members can read the full piece on the site, and it has also been published in full on Today.com.
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