Tulisa Contostavlos was drugged and sexually attacked aged 16.
The 24-year-old singer has revealed she had her drink spiked during a night out and then woke up to find her "so-called friend" having sex with her, before blacking out again and then waking to see the man"s mum standing next to the bed with a cup of tea.
But the "X Factor" judge was too "embarrassed and ashamed" to tell her she hadn"t consented to sex with her son.
Speaking about her shocking ordeal for the first time in her new autobiography, "Honest: My Story So Far", which is being serialized in The Sun newspaper, she says: "I couldn"t even move, let alone get up or speak, and once again I just blacked out.
"I felt so embarrassed and ashamed that I couldn"t bring myself to tell her that I actually hadn"t consented to any of this - even know I knew that there was no way I"d got so drunk that I"d black out like that.
"I knew I"d been drugged. I went into the bathroom and burst into tears. Then I pulled myself together, got dressed and left without saying another word, crying all the way home.
Tulisa blames her "fearless nature and lack of guidance" for getting herself into such a situation, but she still regrets that the man has never been brought to justice.
She added: "I realize 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 out."
Tulisa also admits she went "off the rails" when she was a teenager and got heavily involved with a girl gang, who she would act as a lookout for when they used to visit rich areas of North London and steal handbags.
But the "Young" hitmaker - who used to be referred to as "Whitey" because the other gang members were black - insist she felt "terribly guilty" every time a bag was stolen.
What"s more, Tulisa used to tag along with the group when they performed "dangerous" rip-off scams on men who often used to seek brutal revenge.
She said: "At the time, I suppose, I was hardened to it. It was normal life. I"d gone much too far off the rails to have any qualms about it then."