Signed copy of J.K Rowling’s ‘The Cuckoo’s Calling’ under pen name Robert Galbraith being auctioned off

By Louis Dargavel Corbett via SWNS

A rare signed copy of "The Cuckoos Calling" by author Robert Galbraith before he was revealed to be J.K, Rowling is going on sale.

The creator of the Harry Potter series secretly published a crime novel under the guise of the male debut writer in April 2013.

Galbraith was apparently a former plain-clothes Royal Military Police investigator who had left the armed forces in 2003 to work in security.

"The Cuckoo's Calling" was reasonably well-reviewed at the time but had sold fewer than 1500 copies before the secret was blown.

Within hours, it had risen more than 5,000 places to top Amazon's sales list.

At the time Rowling said she had "hoped to keep this secret a little longer. It has been wonderful to publish without hype or expectation, and pure pleasure to get feedback under a different name."

One of only a few copies of J.K. Rowling’s "The Cuckoo's Calling" signed by the author under the pseudonym will go on sale at Sworders on August 23.

Waterstones booksellers called it “the best act of literary deception since Stephen King was outed as Richard Bachman back in the 1980s'."

The book was published in the UK by Sphere with a first printing of around 1500 copies. It was priced at £16.99 ($20.58).

The signed copy that comes for sale at Sworders with an estimate of £1000-1500 ($1,200- $1,816)-was purchased at the time from London dealership Goldsboro Books.

Rowling/Galbraith’s series of Cormoran Strike books continues to grow, with the sixth book in the series, "The Ink Black Heart," releasing in August.