28/11/2011 06:39 GMT | Updated 28/01/2012 05:12 GMT

Jessie J ditches the catsuits for glam lace-front gown on X Factor

Jessie J made her big X Factor debut as a guest performer during last night's results show - ditching her usual preference for colour-clashing catsuits and skimpy leotards, in favour of a striking floor-sweeping gown.