Rose will be at Old Grumpy's on October 29 from 3pm to 4pm and will be talking to fans and signing books, which will be on sale.
Mrs Leask said she was "over the moon" about the opportunity to meet one of her favourite authors.
"I own four of her books but I've read all 15 of them. She writes thrillers with romance through it. I love the way all of the books are interconnected. A minor character in one book will be the main character in another book.
"I also like the way she doesn't just do police, but writes about firefighters and security consultants."
Old Grumpy's owner Bob Ricketts said it was "a bit of a coup" getting Rose to the store.
"It's amazing how social media like Facebook works. We're just a small shop, not an international chain .
"Rose writes some fantastic stuff and it's tremendous to get her here. It's quite an honour really."
People wanting to attend need to book in advance for the free event.
"The interest has already been phenomenal in the few days since it's been confirmed."
Who is Karen Rose?
• Internationally bestselling author Karen Rose was born and raised in the Maryland suburbs of Washington, DC.
• Her debut suspense novel, Don't Tell, was released in July, 2003. Since then, she has published 14 more novels and two novellas. Her fifteenth novel, Watch Your Back, was released this year.
• Her books have appeared on the bestseller lists of the New York Times, USA Today, London's Sunday Times, and Germany's Der Spiegel, the Irish Times, as well as lists in South Africa and Australia.
- www.karenrosebooks.com