The X Factor is a British television music competition to find new singing talent. The eighth series aired on ITV on 20 August 2011 and ended on 11 December 2011. Dermot O'Leary hosted the main show on ITV, while Caroline Flack and series 6 runner-up Olly Murs co-presented the spin-off show The Xtra Factor on ITV2. Louis Walsh returned to the judging panel and was joined by Gary Barlow, Kelly Rowland and Tulisa. Barlow, Rowland, Tulisa joined the panel replacing judges, Simon Cowell, Dannii Minogue and Cheryl Cole. Series 5 winner Alexandra Burke served as a guest judge for week 4 of the live shows due to Rowland having a throat infection.