The X Factor 2015: Love & Heartbreak theme, Ed Sheeran to perform and what the acts will sing

Prepare to hear some ballads! This week's theme on The X Factor live shows is 'Love & Heartbreak' which will see the contestants picking songs about a whole array of subjects, from first dates to break-ups.

Last week was a particularly crucial one for the contestants as those who got through the third week would officially be part of the line-up for The X Factor Tour 2016, following this series' conclusion. Wild card Monica Michael and Max Stone just missed out on making the cut, however X Factor revealed on their official Facebook page earlier this week that they will bring one act back to complete the line-up. The lucky contestant has yet to be announced.

This weekend only one act will be eliminated, but that doesn't mean that the acts can relax when it comes to their performances. Here's what you can expect from each of the remaining finalists ...

The Boys - Judge: Nick Grimshaw

Ché Chesterman will be singing Yesterday by The Beatles whilst show bad boy Mason Noise is set to perform Nick Jonass' hit single Jealous.

The Girls - Judge: Rita Ora

Ever the daunting task, Lauren Murray will be tackling a Mariah Carey track on tonight's show, as she performs We Belong Together and Louisa Johnson will sing Let It Go by James Bay.

The Over 25s - Judge: Simon Cowell

Cowell's only act left standing after last week's elimination, Anton Stephans, will be taking on Mariah Carey & Boyz II Men's One Sweet Day.

The Groups - Judge: Cheryl Fernandez-Versini

Fernandez-Versini's self-confessed favourite act Reggie 'N' Bollie will be singing a mash-up of Dangerous Love by Fuse ODG and Shut Up And Dance by Walk The Moon whilst 4th Impact, who wowed the judges with their energetic performance last week despite youngest member of the group Celina collapsing in rehearsals, are set to perform Christina Aguilera's Ain't No Other Man.

According to William Hill, Louisa Johnson is this week's favourite to win with betting stakes completely even. Ché Chesterman and Lauren Murray are immediately behind with 10/3 odds, with 4th Impact holding the third favourite to win position with 10/1.

Tune into The X Factor on ITV from 8pm to 9.40pm on 21 November to see the seven acts perform their chosen songs and a special guest performance from Ed Sheeran and Rudimental, who will be singing their single Lay It All On Me. The results show is on from 8pm to 9pm on 22 November, with host Olly Murs performing his latest song Kiss Me and former Wanted star Nathan Sykes treating the audience to a rendition of his solo single Over and Over Again.

For more entertainment news follow A-List on Twitter @Alistinsider