Even rockstar author J.K. Rowling has received letters of rejection

J.K. Rowling is about to have another bestseller on her hands, with the July 31 release of "Harry Potter and the Cursed Child."

In fact, the book — which is actually the script of the two-part London play she wrote with Jack Thorne and John Tiffany — hasn't even been released yet, but it's already the bestselling book of the year on Amazon based on pre-orders alone.

The play follows an adult Potter and his son Albus as they navigate a post-Voldemort world with friends and family.

But before J.K. Rowling's "Harry Potter" series became a commercial and critical hit — spawning films, spinoffs, and the new play — that turned her into a literary superstar, Rowling was struggling to make Potter's story come to fruition.

Her manuscript was rejected by 12 different publishing houses before she finally found a publisher. But even with the incredibly successful "Harry Potter" franchise under her belt, one of Rowling's newer manuscripts was also recently denied.

In March 2016, the author took to Twitter to talk about rejection and share some photos of rejection letters she received for her 2013 novel "The Cuckoo's Calling," which she wrote under the pseudonym Robert Galbraith. She offered the rejection notices for "inspiration, not revenge" and masked the signatures.

In a letter from Constable & Robinson, a representative wrote that the company couldn't publish the novel "with commercial success" and offered tips for publishing and said that "vital information" could be found in "The Writer's Handbook."

The novel was eventually published and has since spawned a series of its own.

Rowling revealed that she pinned her first rejection letter to her kitchen wall, but she didn't share any "Harry Potter" rejections because they are in a box in her attic.

She added that one of the publishers that rejected "Harry Potter" sent a rude rejection for "Galbraith" as well.

But, she said, she had to persevere, and it all paid off in the end — quite literally.

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