Sales of the crime thriller J.K. Rowling wrote under a pseudonym have rocketed since she was inadvertently unveiled as its author. The Harry Potter writer was furious after she was revealed as the mastermind behind critically acclaimed novel The Cuckoo's Calling, which was published under the name of Robert Galbraith. The mystery unravelled when a lawyer, charged with keeping Rowling's secret, accidentally told a family friend, who then tweeted the news and alerted the British press. However, the revelation has given the book a massive boost in sales - it shifted 17,662 hardback copies in the U.K. between 14 and 20 July (13), up from just 43 the week (01-07Jul13) before the news broke. The sales figures made the tome Britain's bestselling hardback book last week (ends21Jul13), with many retailers running out of copies, while signed copies are now fetching more than $1,500 (£1,000) on eBay.com. The writer has since been forced to deny her unmasking was part of a ploy to boost sales, insisting, "It was not a leak or marketing ploy by me, my publisher or agent... If sales were what mattered to me most, I would have written under my own name from the start, and with the greatest fanfare." The Cuckoo's Calling is Rowling's second published work for the adult market, following last year's (12) The Casual Vacancy, and she recently finished work the upcoming 2014 sequel. She completed her seven-part Potter series in 2007.