Sir Terry Pratchett has died at the age of 66, his publisher has confirmed.

The Discworld author had been battling Alzheimer's.

The last tweet from his Twitter account, which was sent earlier today, said: "The End."

The End. - Terry Pratchett (@terryandrob) March 12, 2015

Larry Finlay, managing director at Transworld Publishers, said he was "deeply saddened" by the news.

He said: "The world has lost one of its brightest, sharpest minds."

Sir Terry, who wrote more than 70 best-selling novels, waged a very public struggle with Alzheimer's disease in recent years.

His publisher said he "passed away in his home, with his cat sleeping on his bed, surrounded by his family".

He completed his last book - set like so many of his best-sellers in his creation of Discworld - last year.

Mr Finlay said: "In over 70 books, Terry enriched the planet like few before him. As all who read him know, Discworld was his vehicle to satirise this world; he did so brilliantly, with great skill, enormous humour and constant invention.

"Terry faced his Alzheimer's disease (an 'embuggerance', as he called it) publicly and bravely. Over the last few years, it was his writing that sustained him. His legacy will endure for decades to come.

"My sympathies go out to Terry's wife Lyn, their daughter Rhianna, to his close friend Rob Wilkins, and to all closest to him."