Cher Lloyd has told how she was "scared to death" when she was booed by the studio audience as she clinched a place in the show's semi-finals.
The 17-year-old also hit back at claims she has become a "diva", insisting her youth and inexperience was to blame for her behaviour.
Cher is one of only five acts to make it through to this weekend's penultimate weekend of the hit ITV1 show. But when she was voted through some members of the crowd at London's Fountain Studios gave her a hostile reception.
"At first I was completely mortified by it, my heart started pounding and I was scared to death," she said.
Speaking prior to a secret gig in London, Cher added: "For me to be stood on stage on my own and have people boo me was disgusting. I had nowhere to run to.
"And still now I get really upset about it, but it's okay because there are people out there that actually appreciate me for being me and that's why I'm still here."
Responding to reports of diva-ish behaviour backstage, she said: "I'd like people to still realise I'm only young and sometimes I do not know what I'm doing because I'm still being told what to do. And sometimes I get really scared and I panic. But that doesn't mean I'm a diva."
Cher performed two songs at an intimate gig at London's Hospital Club, organised by show sponsors TalkTalk, along with other X Factor stars.
Sick contestant Matt Cardle had to miss out on performing so he could rest his voice, and One Direction's Zain Malik was absent from the gig because of a "personal matter", show bosses said.