Will Young felt "seedy" being attracted to his male friends as a teenager.
The 41-year-old singer studied at Wellington College in Berkshire, South East England, and he’s admitted to hating himself for being sexually attracted to his school pals.
He shared: "I got to be in the showers with a lot of boys that I fancied, and it made sense that at the time I might be turned on by that.
"But I just felt so disgusting. Properly wrong. Seedy. Manipulative. That I was watching my friends and storing it up in the w*** bank. I felt intrinsically evil."
Will remained quiet about his sexuality for a long time, but things became increasingly uncomfortable for him as he progressed through adolescence.
He told The Times newspaper: "I would wear red New Balance trainers and I became fixated that somebody would see the fact I was wearing red trainers meant I was obviously gay. The fact I was always wearing vintage floral shirts didn’t seem to cross my mind for some reason.
"But the red trainers were a source of constant worry."
Will won the inaugural series of ‘Pop Idol’ in 2002, but he felt under pressure at the time to play down his sexuality.
He explained: "I was slightly neutered, really.
"But also I was a realist. I wasn’t stupid. I wanted to have a career and there are fewer gay people in the world. Like, who wants to see me kiss a man in a pop video? Maybe one in ten people? I used to say, ‘Just do the maths.’"
Will still regrets not speaking out in 2009, when Chris Moyles dedicated a chunk of his BBC radio show to mocking him and his sexuality via a series of spoof songs.
Reflecting on the incident, he said: "It still makes me feel sad in a way, because it did affect how important I felt my sexuality was, and because I didn’t stand up for myself."