Harry Potter author JK Rowling has outed the Headmaster of Hogwarts school.

At a fan event in New York, she revealed that Albus Dumbledore is gay.

Her shock announcement was greeted by applause and gasps of amazement from her audience.

The most successful author of modern times described her seven-book saga as a “prolonged argument for tolerance.”

Dumbledore, who was a significant character in all the Potter books, “was smitten with rival Gellert Grindelwald, whom he defeated long ago in a battle between good and bad wizards.

“Falling in love can blind us to an extent,” she said, according to AP.

She went on to say that he was: “horribly, terribly let down.”