J.K. Rowling, creator of the mass-selling "Harry Potter" books, made an impassioned plea Monday for Britons to vote to stay in the EU, warning in a blog posting against rising nationalism across the world.
The British author, whose novels and films about the boy wizard have become a global phenomenon, said many of those backing a Brexit in Thursday's EU referendum were making a protest "against everything about modern life that scares us".
She condemned US presumptive Republican presidential nominee Donald Trump as a "fascist in all but name", and said his "nationalist cries" had been reflected in the campaign for Britain to end its 43-year membership of the European Union.
She especially condemned an anti-immigration poster by the UK Independence Party (UKIP), led by Nigel Farage, showing refugees trying to come into Europe as "an almost exact duplicate of propaganda used by the Nazis".
"Nationalism is on the march across the Western world, feeding upon the terrors it seeks to inflame," Rowling wrote on her website, in a posting entitled "On Monsters, Villains and the EU Referendum".
"Every nationalist will tell you that their nationalism is different, a natural, benign response to their country's own particular needs and challenges, nothing to do with that nationalism of yore that ended up killing people.
"Yet every academic study of nationalism has revealed the same key features."
Rowling said the EU was not perfect, but added research had showed Britons were "ignorant of what it gives us".
"How can a retreat into selfish and insecure individualism be the right response when Europe faces genuine threats, when the bonds that tie us are so powerful, when we have come so far together?" she wrote.
She concluded: "In a few days' time, we'll have to decide which monsters we believe are real and which illusory."