This year's X Factor judges have been assigned the categories they will be mentoring for the reality show, with Gary Barlow and Kelly Rowland nabbing those most likely to win.

New judges Barlow and Rowland will take on the boys and girls categories respectively. Past X Factor series have gone on to spawn winners including Matt Cardle and Leona Lewis from those categories.

Meanwhile, last original judge standing Louis Walsh is in the unenviable position of mentoring the over-25's – a category that hasn't won since flop series one champ Steve Brookstein failed to set the charts alight.

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Newcomer Tulisa Contostavlos of N-Dubz will mentor the groups. Although this category has never won the X Factor, it has produced surprise success stories such as JLS and G4.

Rumour has it that Gary Barlow will bring in the big guns to ensure he triumphs as the winning judge – it is said that Take That bandmate Robbie Williams will help him mentor the boys. Williams dueted with contestant Olly Murs on the show in 2009.

The judges are each taking eight acts through to the Judges Houses stage, during which they will whittle the list of hopefuls down by half before the live rounds begin.