The X Factor 2015: Reinvention theme week, what will they be singing and the double elimination

This week's theme on The X Factor live shows is 'reinvention', which will see the contestants "take a classic song and totally re-invent it and make it their own" according to judge Nick Grimshaw speaking on the Xtra Factor special. We're not quite sure how picking an existing song and making it your own can constitute a theme, when in the past they've been expected to do that every performance regardless, but heck, if Grimshaw says "it's good"...

The theme wasn't the only news announced on the show either. Girl group Alien Uncovered and Overs singer Bupsi Brown felt how brutal it can be when more than one finalist goes at the same time in one week, and there won't be any letting up this Sunday either. That's right, week two is following suit with another double elimination.

But before you can even begin to speculate who will be going home, they each have to perform their chosen tracks on tonight's show. Here's what you can expect from each of the finalists...

The Boys - Judge: Nick Grimshaw

Seann Miley Moore will be taking on California Dreamin' by The Mamas and the Papas, while Che Chesterman will also be channelling the sixties with his rendition of The Supremes' You Can't Hurry Love. Mason Noise is to cover another retro tracks, 1980s Teardrops by Womack & Womack.

The Girls - Judge: Rita Ora

Lauren Murray is keeping things a little more modern, as she'll be singing James Bay's Hold Back The River, whereas Monica Michael will be performing Crazy In Love by Beyonce. Kiera Weathers is planning to take on Mark Morrison's Return Of The Mack and youngest in the competition, Louisa Johnson, will be singing Michael Jackson's iconic Billie Jean.

The Over 25s - Judge: Simon Cowell

Probably most surprising of all is Anton Stephan's decision to performa mash-up of Meghan Trainor's All About That Bass and Jessie J's Bang Bang, so fans of the show will certainly be keen to see how the former backing singer tackles that one. Meanwhile Max Stone is set to perform Somewhere Over The Rainbow/What A Wonderful World, made famous by 757-pound Hawaiian Israel Kamakawiwo'ole.

The Groups - Judge: Cheryl Fernandez-Versini

Like the Over 25s, the Groups will also both be doing medleys, with Reggie 'N' Bollie singing What Makes You Beautiful/Cheerleader by One Direction/OMI and 4th Impact performing Sound Of The Underground/Boom Clap, from Girls Aloud and Charli XCX respectively.

According to William Hill, 17-year-old Louisa Johnson is the current favourite to win, with odds of 5/4 but she has competition hot on her tails in Che Chesterman at 11/2. Filipino girl band 4th Impact are third at 7/1.

Tune into The X Factor on ITV from 8pm to 10.10pm on 7 November and from 8pm to 9pm on 8 November.

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