Harry Potter author JK Rowling has donated £1m to the Better Together anti-Scottish independence campaign.
The millionaire author, who lives in Edinburgh, said an independent Scotland would not have an easy ride from England, Wales and Northern Ireland who would become three "bitter neighbours".
Writing on her website, Rowling said that, while she is "no fan of the current Westminster Government", she has concerns about the economic risks of independence.
"My hesitance at embracing independence has nothing to do with lack of belief in Scotland's remarkable people or its achievements," she wrote.
"The simple truth is that Scotland is subject to the same 21st century pressures as the rest of the world. It must compete in the same global markets, defend itself from the same threats and navigate what still feels like a fragile economic recovery.
"The more I listen to the Yes campaign, the more I worry about its minimisation and even denial of risks."
She continued: "The more I have read from a variety of independent and unbiased sources, the more I have come to the conclusion that, while independence might give us opportunities - any change brings opportunities - it also carries serious risks."
Referring to her donation to Better Together, she wrote: "I wanted to write this because I always prefer to explain in my own words why I am supporting a cause and it will be made public shortly that I've made a substantial donation to the Better Together campaign, which advocates keeping Scotland part of the United Kingdom."
She added: "If we leave, though, there will be no going back. This separation will not be quick and clean: it will take microsurgery to disentangle three centuries of close interdependence, after which we will have to deal with three bitter neighbours.
"I doubt that an independent Scotland will be able to bank on its ex-partners' fond memories of the old relationship once we've left. The rest of the UK will have had no say in the biggest change to the Union in centuries, but will suffer the economic consequences."