Everything you need to know about the X Factor Bootcamp weekend

What is The X Factor's Bootcamp?

After the closed-room auditions, all of the acts who got three or more yeses from judges Simon Cowell, Nicole Scherzinger, Sharon Osbourne and Louis Walsh made it through to Bootcamp.

This is the stage where the acts are given a song, put into groups of four and then perform once again for the judges.

Those who are successful make it through to the terrifying Six Chair Challenge, while those who aren't have to exit the competition and head home. At least they get a hug from Dermot O'Leary on the way out, if nothing else.

How does Bootcamp work this year?

There are three elements of Bootcamp the wannabe singers have to survive. The first is the dreaded Wall of Songs. Introduced last year, this evokes complete and utter "carnage". Yep, that's the word Dermot used to describe this daft gimmick, and we can see why.

There's a metal frame at one end of a warehouse and the contestants at the other. At the sound of a klaxon they all have to scrum forward and grab the song they want to perform from the wall where 140 titles have been posted. Here's the mayhem that ensued last year:

Pretty bonkers, no?

Songs on the wall this year include I Wanna Dance With Somebody by Whitney Houston, Treat You Better by Shawn Mendes, Cheap Thrills by Sia, Heroes by David Bowie and History by One Direction.

After this, the acts are then put into groups of four (a mix of groups and individuals) and must perform the song they chose from 'The Wall' for the judges the next day. Then and there, the judges will decide who goes through to the second stage of Bootcamp.

There's a second stage of Bootcamp?

Yep, you read that correctly. There's a second stage of Bootcamp. For the first time this year, the contestants will be singing in front of a live arena audience after they've made it through their initial performance.

Filmed at Wembley Arena over three days, they will once again need to impress the judges in this final stage of Bootcamp before the Six Chair Challenge.

Who has made it through to Bootcamp?

If a singer or group got three or more yeses in the closed-room auditions, they immediately made it through to Bootcamp.

Here are all of the acts who triumphed in the auditions and who will be performing again this weekend:

Week one

Grace Davies, 20, Blackburn - performed her original song, Roots

Holly Tandy, 15, Barnsley - performed If I Ain't Got You by Alicia Keys

Jack & Joel, both 22, London - performed an Ed Sheeran medley

Elisangela Mahogany, 34, Brazil - performed Shape of You by Ed Sheeran

Rwanda Shaw, 21, Liverpool - performed Issues by Julia Michaels

Jack Smith, 23, Oxfordshire - performed Hey Ya by Outkast

Kayleigh Taylor, 27, Liverpool - performed My Immortal by Evanescence

Sam Black, 27, Liverpool - performed Runaround Sue by Dion

Rak-Su, group with members Ashley, Miles, Jamal and Mustafa from Watford - performed their original song, I'm Feeling You

Shanaya Atkinson-Jones, 19, County Durham - performed Say Something by A Great Big World ft. Christina Aguilera

Gaga Lord, 40, Philippines - performed Diamonds are Forever by Shirley Bassey

Nicole Caldwell, 27, Paisley - performed Purple Rain by Prince

Georgina Panton, 20, Birmingham - performed Love On The Brain by Rihanna

Jordan Rabjohn, 22, Sheffield - performed his original song, Mexico

Lloyd Macey, 23, Wales - performed Lay Me Down by Sam Smith

Week two

Talia Dean, 32, Hounslow - performed I Put A Spell on You by Nina Simone

Liaa, 20, London - performed The Trouble With Love by Kelly Clarkson

Drew Wedlake, 22, Bristol - performed Seven Nation Army by The White Stripes

New Dynamixx, group with members Yvonne, Jake, Charlotte, Izzy and Codie - performed a medley of Little Mix and Jonas Blue

Kevin Davy White, 29, London - performed Man's World by James Brown

Rebecca Grace, 22, Essex - Piece by Piece by Kelly Clarkson

The Cutkelvins, group with members Jay, Shereen and Kay, Lanark - performed Runnin’ (Lose It All) by Beyoncé and Naughty Boy

Daniel Quick, 18, Bristol - performed Your Song by Ellie Goulding

Deanne, 22, Anguilla - performed I Have Nothing by Whitney Houston

Aidan Martin, 27, London - performed his original song, Punchline

Week three

Benji Matthews, 17, Cornwall - performed If I Ain't Got You by Alicia Keys

Tracey Leanne Jefford, 34, Middlesex - performed Will You Still Love Me Tomorrow by The Shirelles

Russell Jones, 25, Wales - performed I Wanna Be Like You from The Jungle Book

Nicole Simpson, 22, Scotland - performed Just Hold On by Drake

Gregor Coleman, 24, Glasgow - performed Stay by Rihanna

Sean and Conor Price, 17 and 15, Ireland - performed All Along The Watchtower by Jimi Hendrix

Chloe Rose Moyle, 16, Lancashire - performed Be My Baby by The Ronettes

Harry Holmes, 20, Liverpool - performed his original song, Girl Who Stayed The Night

Imagen Harrison, 17, Stoke - performed Suitcase by Emeli Sandé

Descendance, mother Debye, 40, and daughter Hayley, 20, Belfast - performed Can't Hold Us by Macklemore

The Clique, group with members Corey, Jason and Rowland - performed Touch by Little Mix

Taliah Dalorto, 19, Essex - performed Ain't No Way by Aretha Franklin

Gary Barker, 29, Liverpool - performed Change Is Gonna Come by Sam Cooke

Week four

Spencer Sutherland, 24, USA - performed Let’s Get It On by Marvin Gaye

ITG, group with members Alex and Leon, Norwich - performed Don't by Ed Sheeran

Matt Linnen, 28, Essex - performed Trouble by Ray LaMontagne

Scarlett Lee, 19, Surrey - performed Rise Up by Andra Day

Rai-Elle, 16, Croydon - performed Sail by Awolnation

Brad Howard, 30, Manchester - performed Lately by Stevie Wonder

Slavko, 31, Montenegro - performed End of Time by Beyoncé

Alisah Bonaobra, 22, Philippines - performed Listen by Beyoncé

Jenny Ball, 26, Blackpool - performed Titanium by David Guetta ft. Sia

Rebel Elijah, 21, Cardiff - performed This Is How We Do It by Montell Jordan

Just Us, group with members Anna-Maria and Carol - performed Hasta Mañana by ABBA

Berget Lewis, 45, Amsterdam - performed Purple Rain by Prince

What happened to Anthony Russell?

The promising singer was a favourite when he made it through the auditions – especially after it was revealed he had initially auditioned for the show way back in 2007!

However, Anthony has now pulled out of the competition for personal reasons.

Russell, who became a firm favourite among fans – and the judges – after his performance of Issues in the audition stages, made the decision to withdraw himself, a spokesperson for the series told RadioTimes.com.

An official statement explained that Anthony left the show following his successful audition.

“Earlier this month, due to personal reasons, Anthony withdrew from the show. We are sad to see him go and wish his all the best for the future”, it explained.

A source close to The X Factor added, “Anthony has been going through some personal issues for some time – as he sang about at his audition. Those issues were still affecting him. So everyone has urged him to concentrate on getting himself better right now.”

What happens after Bootcamp?

Next up for the plucky performers is the Six Chair Challenge. This is where each judge has only six spots available for their Judges' Houses, and so all of the successful singers through in their category must vie for a spot on their team.

Eventually, all of the singers are whittled down and just six acts will remain for each judge. It's these singers who are then flown around the world to Judges' Houses where they compete for a spot on the live shows.

The X Factor airs 8pm Saturday September 30 and 7.30pm on Sunday October 1 on ITV.