Alexandra fears 'karaoke' comparisons

X Factor contestant Alexandra Burke has expressed concern that her rendition of a Mariah Carey classic will lead to "karaoke" comparisons by Simon Cowell.

The singer said she is worried that she will not be able to live up to the judge's expectations after he likened her to Whitney Houston earlier in the series.

Burke has received intensive vocal training from coach Yvie Burnett and achieved a breakthrough when she learned to sing from her stomach and not her throat, a technique she has struggled to master in recent weeks.

She was given a speaking ban last month in order to preserve her voice.