X Factor judge Tulisa Contostavlos has said she was drugged and sexually abused when she was 16, and did not tell her family or the police.
The pop star has spoken about the attack for the first time in her new autobiography, Honest, in which she also reveals her involvement in a girl gang that took part in criminal activity.
Contostavlos, 24, revealed the events from her teenage years in The Sun, where her book is to be serialised all week.
Despite warning friends she did not want to take part in drug-taking at a rave where she watched them "dropping pills in one another's drinks", the TV judge says she blacked out.
She said: "When I came round again, I was in a bedroom and my so-called friend was on top of me, having sex with me.
"I couldn't even move, let alone get up or speak, and once again I just blacked out."
The singer says she now believes the boy should have been brought before the courts.
She said: "I realise now, of course, that I'd done nothing to be ashamed of and the boy in question should have been prosecuted, but I was young and confused and not strong enough to speak up."
Now one of the most famous women in Britain, Contostavlos says she is glad to be away from her old way of life, but says it still "feels normal" for her.