Dermot O'Leary hosts the next stage in the star-studded version of the singing contest, which features further live performances in London. The remaining acts have got through the initial rounds in Los Angeles and the judges' deliberation, and now must battle it out for the chance to be crowned champion and win a record deal. They will have the support and coaching of the judges, with Simon Cowell taking charge of the Groups, Nicole Scherzinger mentoring the Overs, and Louis Walsh looking after the Unders.