The X Factor is a British television music competition to find new singing talent. The eighth series commenced airing on ITV on 20 August 2011 and ended on 11 December 2011. The winner was Little Mix, a four-piece girl group known earlier in the series as Rhythmix, consisting of members Jesy Nelson, Perrie Edwards, Leigh-Anne Pinnock, and Jade Thirlwall. They became the first act in the groups category to win in the UK show's history with new judge Tulisa emerging as their winning mentor. Dermot O'Leary presented 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, replacing Konnie Huq from the previous year. Louis Walsh returned to the judging panel and was joined by Gary Barlow, Kelly Rowland and Tulisa. Barlow, Rowland and Tulisa joined the panel as replacements for former judges, Simon Cowell, Dannii Minogue and Cheryl. Series 5 winner Alexandra Burke served as a guest judge for week 4 of the live shows due to Rowland having a throat infection.