There’s been a huge shake-up on the panel this year, with three of the four mentors making their debuts on the show. We take you through all you need to know about this year’s X Factor judges…

Louis Walsh

The Irishman is the only ever-present judge in the history of the show but it’s not normally worth considering his acts in the X Factor betting markets. He may have found success with Westlife and Boyzone but finding an X Factor winner has been much tougher – in fact, Walsh’s only success on the show was Shayne Ward way back in 2005. Admittedly he has managed some poor categories in recent years, notably the over-28s last time around, but it’s difficult to ignore his disappointing record of producing winners on the show. Louis has been handed the 'overs' X Factor category once again this season - a section which hasn't won the competition since Steve Brookstein in the very first series.

Gary Barlow

There’s rumours that Barlow will be this year’s ‘Mr. Nasty’ and given Simon Cowell’s success with that persona, it should stand him in good stead. As one of the greatest singer-songwriters in British history, he has emerged as the early X Factor favourite in the ‘Winning Manager’ market and given his previous track record it’s hard to disagree with that. Gary will be in charge of the boys this year, who have won the last 2 renewals.

Tulisa Contostavlos

Being the youngest judge in the history of the show, Tulisa is somewhat of an unknown quantity. However, given female judges have mentored the last 4 successive X Factor winners, her odds could prove to be value in the ‘Winning Manager’ market. She has reportedly already been involved in some interesting altercations during the X Factor auditions, which should make for good TV. Tulisa is mentoring the groups, who have never won the X Factor to date.

Kelly Rowland

Will we have another X Factor judges war between the girls? There were always rumours that Cheryl Cole and Dannii Minogue didn’t get on, so it will be interesting to see how Rowland’s relationship with Tulisa develops. Being one-third of massive girl group Destiny’s Child certainly gives her the credentials to spot a future pop star. However, it may be worth waiting to see how the American interacts with the UK audience before investing in her X Factor odds to mentor the winner. Kelly will be looking after the girls, who many regard as the strongest category in the 2011 X Factor.