Beyoncé has revealed that the vocals on her song 'XO' were recorded when she was ill.

The track features on the singer's surprise 2013 self-titled album and it became one of the record's lead tunes.

However, Beyoncé has now revealed that the vocal track used on the song was actually a demo recording cut to tape when she had sinus problems.

She told Out magazine: "I was sick with a bad sinus infection. I recorded it in a few minutes just as a demo and decided to keep the vocals. I lived with most of the songs for a year and never re-recorded the demo vocals. I really loved the imperfection."

Speaking meanwhile about sexuality and equality, the superstar singer said in the same interview:

"Being that I am a woman in a male-dominated society, the feminist mentality rang true to me and became a way to personalise that struggle. But what I'm really referring to, and hoping for, is human rights and equality, not just that between a woman and a man.

"So I'm very happy if my words can ever inspire or empower someone who considers themselves an oppressed minority. We are all the same and we all want the same things: the right to be happy, to be just who we want to be and to love who we want to love."