Beyonce Knowles has agreed to appear on the cover of a gay magazine.

The singer-cum-actress will front the American publication Instinct, and reveals she made the shock move thanks to her gay uncle.

"I was raised by my uncle who passed away with AIDS a couple of years ago. He was my mother's best friend," she said, in the magazine's accompanying article.

"He brought me to school every day. He helped me buy my prom dress. He made my clothes with my mother. He was like my nanny. He was my favourite person in the whole world.

"I never mixed Christianity with how I felt (about him). I am about faith and spirituality more so than religion. Doing right by others and not judging."