6/8. Only half the original line-up remains as the pressure steps up a gear in tonight's edition of the showbiz karaoke contest. Each duo will perform an acoustic version of a classic song, but it must be in a musical style they've not sung before. Only viewers' votes can decide who'll make it through to the semi-final. Which TV stars from Matt Allwright , Mark Moraghan , Nicky Campbell , Chris Fountain , Sian Reeves , Gaby Roslin , Fiona Bruce and Penny Smith have made it through to this stage - and which warbling couple will be shown the door? Tess Daly and Vernon Kay play host. <s)