X Factor contestant Tamera Foster committed the ultimate singing faux-pas when she forgot the words to her song in what Gary Barlow described as a "car crash" performance.

Last week the 16-year-old came under fire from the judges for forgetting the lyrics to the song Diamonds Are Forever. Explaining to her mentor, former PussyCat Doll Nicole Scherzinger, exactly what was going on in her head at the time Foster said: "I think I just let everything get to me in the performance I forgot my words in the sound check and it got to me. I was really angry with myself because I thought I let myself down. I need to work really hard this week. there's no room for mistakes."

But despite her determination to wow the judges this week, the singer goofed up again with a flawed rendition of James Arthur's 2012 winner's single Impossible, as she forgot the opening lines to the song.

Foster didn't as much wow the judges as leave them with jaws dropping in stunned disbelief. Looking despondent, Foster faced the judges in turn for their comments. Louis Walsh simply said: "What can I say? You are the contestant in this competition with the potential to be a world-wide superstar. But what happened to your words? You need to remember your words. You keep forgetting your words. You got most of them right. It's so frustrating to watch someone who could be a potential superstar messing up her words. You cant do it anymore."

Sharon Osbourne tried her best to console the aspiring star saying: "Don't get down on yourself. You tick all the right boxes. You've got it all going on. I don't know what the problem is with the words. You did good. You kept on. Don't get down on yourself, because you're going to be a star."

Take That star Gary Barlow took a characteristically tougher stance saying: "It's hard to watch. It's really hard to watch. I don't know how we solve this problem. We've seen it three or four times. It's excruciating watching a car crash happen."

But Foster's mentor Scherzinger stood by her act all the way saying: "Tamera I'm so proud of you tonight because you kept going and you fought through it and you're only 16 years old and you keep on this path and nothing will be impossible for you."

Speaking to show host Dermot O'Leary after the performance, a defiant Foster said: "I think I got inside my head too much, but you know what - I put everything I had into that song."

Closing the show with a powerful rendition of Leona Lewis's Bleeding Love, bookies favourite to win the show, Sam Bailey took the opportunity to show her support for her fellow contestant with a swift rebuttal for Walsh on her behalf, saying simply, "I'm sorry Louis but if I had talent like that when I was sixteen..."

Foster showed signs of nerves early on in the audition process, most notably forgetting the lyrics to a classic Whitney Houston song during the arena auditions.

Find out which of the six contestants is voted out on The X Factor results show on Sunday 24 November at 8pm.