Harry Potter author J.K. Rowling has showed off her rejection letters on Twitter, from when she pitched her detective novel series under the name Robert Galbraith.

A fan on Twitter asked Rowling to share her Harry Potter rejection letters, of which she famously received many, but Rowling replied that she'd stored those in the attic.

What she did have nearby, however, were the rejection letters for her alter ego, Robert Galbraith. 

Robert Galbraith is Rowling's pseudonym under which she wrote The Cuckoo's Calling about private detective Cormoran Strike.

Neither letter has any harsh words for Galbraith's tale. One letter said the publisher has been absorbed by a larger company and simply was not taking submissions. 

"I regret that we have reluctantly come to the conclusion that we could not publish it with commercial success," began the other letter Rowling shared. It offered Galbraith advice on how to pitch a book and how the cover letter could be improved. 

Rowling said she removed the names on those letters as they were meant to be inspiration to other writers, not revenge. 

These two letters were among the many rejections Rowling received in attempting to pitch The Cuckoo's Calling, including one of the publishers to which she'd attempted to pitch Harry Potter decades earlier. 

After the discovery that Galbraith was in fact Rowling in July 2013, Orion Books editor Kate Mills tweeted that she'd been among the editors who rejected the detective novel. 

Rowling managed to remain anonymous for a few months following The Cuckoo's Calling, having settled on Little, Brown and Company as the publisher in 2013. An investigation by The Times revealed Galbraith was Rowling soon after the book's publication, causing the book to turn from a small success to a top seller on Amazon. 

The author wasn't the only one to discuss her rejections online.

The writer of Chocolat, Joanne Harris, replied to Rowling's tweets saying that she'd turned her letters into a sculpture of a phoenix.

As for advice on how authors can keep pitching while receiving rejections, Rowling had this to say: