J.K. Rowling has spent £2.5 million on a new mansion - without even viewing it properly.

The 'Harry Potter' author - who has an estimated fortune of £560 million - splashed out on the property in Edinburgh Scotland, last month, and even promised the owner an extra £300,000 if he vacated the building before the festive season.

A source told The Sun newspaper: "The owner received a call from the estate agents telling him there was a viewer and asking him to meet her at the house to show her around.

"She only looked at a couple of rooms, she didn't even go upstairs before telling the owner to name his price.

"He hadn't even recognised her but he had worked out her identity when she called the next day, offering to pay more if he could be out in a fortnight and leave all the fixtures and fittings.

"She explained that she wanted to host a Christmas party."

The 31-room mansion features a games room, a bar and several acres of ground with specially imported French trees. It is thought the previous owners paid just £500,000 for the house.

The 44-year-old writer - who is married to Dr. Neil Murray, with who she raises son David, six, and daughters Jessica, 16, and Mackenzie, five - also owns a house in London and three other Scottish homes, worth a total of £12 million.