The nation's favourite singing show returns this weekend with the start of the live rounds and reveals this year's four wildcards. Each of the final 16 contestants will sing their hearts out on the live stage with judges Louis Walsh, Sharon Osbourne, Nicole Scherzinger and Simon Cowell resuming their seats behind the judges' desk to battle it out with their contestants in the hope of impressing the audience at home. This year Louis has the Boys, Nicole the Overs, Simon the Groups and Sharon the Girls, with resident host Dermot O'Leary leading the proceedings and keeping the judges in check along the way. Throughout the live shows an outstanding line-up of guest stars perform.