After publishing "Harry Potter" and her non-magical-themed "The Casual Vacancy," you don't think JK Rowling is through with writing, do you? Of course not, the bestselling British novelist won't let her billions and her fame get in the way of her love of writing. She has just admitted to using a decidedly masculine pen name to publish the detective novel "The Cuckoo's Calling."

Rowling used the pseudonym Robert Galbraith to publish her book through Sphere, the same imprint at Little, Brown Group that published "The Casual Vacancy," her first non-Harry Potter book since the series' end.

The Sunday Times has revealed her secret after it investigated how Galbraith, a first-time author with a background in the army, could write such an assured novel.

"The Cuckoo's Calling" follows the story of a one-legged private detective named Cormoran Strike who, along with his office temp assistant Robin Ellacott, has been tasked to investigate the death of a supermodel.

Billed as a "classic crime novel" that is written in the style of P.D. James and Ruth Rendell by the paper, "The Cuckoo's Calling" opened to acclaimed critical reviews in April, but to average sales of 1,500.

However, since UK paper "outed" her as the real author, the detective book's sales have gone up to 156,866% on Amazon. New Statesman reported that from 4,709 rank on Amazon's bestsellers list, it is now at number three, proving Rowling's name alone is magical.

"I had hoped to keep this secret a little longer, because being Robert Galbraith has been such a liberating experience. I has been wonderful to publish without hype or expectation, and pure pleasure to get feedback under a different name," Rowling told The Sunday Times in a statement.

Her publisher even gave Galbraith a fictional back story:

"Born in 1968, Robert Galbraith is married with two sons. After several years with the Royal Military Police, he was attached to the SIB (Special Investigation Branch), the plain-clothes branch of the RMP. He left the military in 2003 and has been working since then in the civilian security industry. The idea for protagonist Cormoran Strike grew directly out of his own experiences and those of his military friends who have returned to the civilian world. 'Robert Galbraith' is a pseudonym."

This isn't the first time Rowling has used a pseudonym to help publish her books. The 47-year-old author, whose real name is Joanne, used JK Rowling when her publishers demanded that she use two initials rather than use her feminine name because they feared that young boys would not want to read her "Harry Potter" series if they knew it was written by a woman.

Using a pen name with a completely different background from their own isn't unusual for authors. In Australia, erotic romance author Natasha Walker has been revealed to be a man in real life.

John Purcell admitted to writing the popular "mummy porn" trilogy "The Secret Life of Emma" and using a feminine pen name to be able to connect with his target readers.

Related:

Bestselling Australian Erotica Author Natasha Walker Reveals Secret Life As A Man [Read]