Robbie Williams has sealed his comeback by joining The X Factor - the pop star has become this series' first celebrity mentor. Skip related content
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The finalists were given a crash course in pop music from the Angels singer, who spent a week guiding the wannabees.
All the hopefuls have been holed up at London's Soho Hotel and given the chance to sing Williams' songs as he accompanied them on the piano and doled out advice.
Williams, who admits he's a huge fan of the show, will also be appearing live at the weekend to perform his new single Bodies.
Yusuf Islam, the artist formerly known as Cat Stevens, is strolling back onto the stage after a break of 33 years.
