Rowling took questions from an audience of 1,600 students. A 19-year-old from Colorado asked about the avuncular headmaster of Hogwarts School: 'Did Dumbledore, who believed in the prevailing power of love, ever fall in love himself?'
The author replied: 'My truthful answer to you...I always thought of Dumbledore as gay.' The audience reportedly fell silent - then erupted into prolonged applause.
Rowling, continued: 'Dumbledore fell in love with Grindelwald [a bad wizard he defeated long ago], and that added to his horror when Grindelwald showed himself to be what he was. To an extent, do we say it excused Dumbledore a little more because falling in love can blind us to an extent, but he met someone as brilliant as he was and, rather like Bellatrix, he was very drawn to this brilliant person and horribly, terribly let down by him.'
Amazed by the warm reaction of the audience, Rowling, on her first US tour in seven years, joked: 'Just imagine the fan fiction now.'