Viewers saw X Factor judge Tulisa Contostavlos break down in tears after choosing not to put one hopeful through to the final 12.
She and fellow panellists had to make tough decisions about who to put into the dozen singers who go forward to the live stages of the show.
Among the acts to head through with a chance of winning were popular performer such as Melanie Masson, Lucy Spraggan and bookies' favourite Ella Henderson.
But Contostavlos was left with tears in her eyes as she let Amy Mottram go last night, saying she was not sure she had made the right decision.
Mottram has been given a lifeline however as one of the four acts who will battle it out to be the "wildcard" in the first live heat on October 6, with viewers voting which should be saved.
The four judges - Gary Barlow, Nicole Scherzinger, Louis Walsh and Contostavlos - spent days with their acts at the judges' houses stage of the contest to whittle them down.
Each judge, accompanied by their guest mentors who included former X Factor judge Cheryl Cole, had to slim their team down from six to three acts, making nailbiting choices based on their acts' performances, and their prospects of a music career.
Masson, 44, has already had a taste of the music business with her own deal and session work and saw the show as her "last chance" of a full-time music career.
Singer-songwriter Spraggan struck a chord with viewers with her performances of her own tracks so far in the series. A change in the rules to allow acts with management deals into the contest has encouraged more entrants with their own material.
And show bosses are allowing them to perform their self-written songs as well as strum along this year, in a first for the live shows.
Henderson is way out in front on 11/8 to win the title according to bookmaker William Hill.
Barlow said: "This year we really have got the cream of the crop with our finalists and it was tough for all of us to choose our three acts. The standard of talent has gone up this year and I think it's the best ever line-up of finalists.
"The live shows will feel very different this year too as contestants can sing their own songs and play guitar - I can't wait for Saturday."
The 12 finalists in this year's X Factor have been announced:
Location: From Glasgow but lives in north London
The mum-of-two said she wants to win for everyone "my age who feels their dream is over".
Melanie has two children, Rua, five, and Ramsay, three, with her husband the Scottish actor, Forbes Masson.
She said if she wins she will celebrate by buying a camper van and taking her family around Scotland.
Melanie also wants them to be proud of her success.
She said: "Thanks to my husband I've been so lucky to be able to be a full time mummy for all of their pre-school years and more, but now I want to make them proud of me and see me singing on a big stage."
It is second time lucky for Carolynne after she lost out at the judges houses section last year and she is determined to make up for that failure.
She said: "Last year was my nightmare year, probably the worst year of my life. I know what it feels like to get a no, and I know what it feels like to watch the show knowing that you could have been a part of it. It means the world for me to be here again."
Carolynne, who said she will bring "girly glamour and giggles" to this year's show, wants to win for her parents.
She said: "I'd like to pay off my mum and dad's mortgage as they mortgaged their house for me when I was 20 to help fund my move to London and help me pursue my career. I owe them everything."
Location: Pinner, London
Singer-songwriter Kye has been working for his uncle's business as a chimney sweep for the past few years but has never given up on music.
He said: "One day I was covered in soot and the next day I was walking onto a stage in front of thousands of people. Being able to sing and be judged on nothing but your vocals and your ability was just amazing. The audience are the ones who determine whether they like you or not; not a guy in an office. Every day there has been a totally new experience for me, sometimes it's scary but it's amazing at the same time."
Kye said if he wins he will take his mother on holiday because she has supported him "every step of the way over the past ten years".
He said: "She's felt all the disappointment I have felt, if not more. I owe it to her after all I've put her through."
James writes his own songs, raps and plays the guitar, but only applied for the show after a friend encouraged him to do it.
But he has lost the nerves as the show has gone on and is looking forward to the live shows.
He said: "I can't wait, none of the judges scare me. At the moment I'm fearless in that respect."
He has promised to bring "versatility, passion and raw emotion" to the show.
The tattooed singer said his song-writing skills could help him win though he has also impressed with his take on a series of cover versions - including Tulisa's song Young.
The party-loving clubber has promised to "bring the X to the X Factor" and wants to record dancefloor anthems.
Rylan has been very impressed with his mentor Nicole Scherzinger who he described as "amazing".
He said: "She's the most stunning woman I've ever met in my life. I even questioned my sexuality when I met her. She's so amazing and we're so on the same level idea wise it's unreal, she's such an asset to me and I hold her very dear."
If he wins he will celebrate in low-key style - with a milky coffee - after he stopped drinking them when he was told they were bad for his throat.
The supermarket worker turned singer wowed the judges in the very first show with his version of At Last by Etta James and says his strong vocals make up for his quiet personality.
He said: "I'm not confident at all with any aspect of myself but singing is my way of expressing myself because talking is not my strong point at all."
Jahmene grew up singing with a choir at his local church and said his love of singing will help him combat any nerves at the live shows.
He said: "The judge that scares me most is myself, no one's as hard on me as I am."
Location: Charlton, southeast London
The bike mechanic wants to win so she can provide a better life for her six-year-old daughter Caiden - starting with a trip to Disneyland.
She thinks there is a gap in the market for her style of music and says her mentor, Tulisa, can help her fill it.
She said: "I have been really looking forward to getting to know the real her and I feel that I kind of do now. What you see on the TV really is what you get; an honest, straight talking and creative person. As a mentor she has taken the time to come and personally view our rehearsals and has also exchanged numbers with us so that we can contact her with any issues we might have."
But she is worried about how Gary Barlow will judge her because she is such a big fan of the Take That frontman.
She said: "I think Gary will be the scariest to perform for. I admire Gary for various reasons but his song writing really inspires me so to have him really slate something would really hurt."
The schoolgirl singer-songwriter, who has just finished her GCSEs, admits she is nervous about the live shows but staying positive.
She said: "I'd say I'm filled with excitement and I just feel like the luckiest girl in the world right now."
She impressed the judges with her first audition when she sang a song inspired by her late grandfather and she says she can only get better.
Ella said: "I believe that I have a lot to give and I'm fully dedicated to my music. I know that by doing this show I'm going to grow as a performer and my confidence will build up each week."
Location: Buxton, Derbyshire, but lives in Sheffield
Lucy caused a storm in her first audition where her performance of her own song, Last Night, got her a standing ovation and has been watched on YouTube more than 11 million times.
She said: "Every step of this process has been so overwhelming for me, from seeing the crowd reaction to my own song through to Tulisa giving me the yes at Judges Houses, and now I just can't wait to show people what I can do on a live platform."
She has been gigging for the last few years as well as holding down different jobs including being a tour guide and a silver service waitress.
GMD3 (Greg, Dan and Mickey)
Age: 18, 19 and 18 respectively
Location: From Essex, Cleethorpes and Porthcawl originally, but live in Windsor now
The trio are hoping their "unity as a group" pulls them through the live shows.
The best mates met at school more than five years ago and have been together ever since.
Mickey said seeing other acts go on from the show and have huge hits inspired them to give it a go.
Dan admits they are nervous but said it is not because of the judges, saying: "All of them are absolutely lovely."
MK1 (Charlotte Rundle and Simeon Dixon)
Age: 19 and 24 respectively
The duo say they are "delivering the underground to the overground" and think the time is right for their mixture of dubstep, pop and hip-hop to be a success.
They auditioned with another friend, Will, but carried on as a duo after the panel said he had to go.
But they have stayed friends and Will still shares a flat with Charlotte.
The pair admit to a few nerves ahead of the live shows and want to impress one judge in particular.
They said: "The judge that scares us the most is Louis - the last person we want to upset is our mentor."
Union J (Jamie Hamblett (JJ), George Shelley, Josh Cuthbert, Jaymi Hensley)
Age: 24, 19, 20 and 22 respectively
Location: from Newmarket, Bristol, Ascot and Luton
The foursome, who claim they are "normal down to earth guys who love to sing", started out as a trio.
Jaymi, Josh and JJ auditioned for The X Factor as Triple J and got through to Bootcamp before Louis added 19 year-old George Shelley to the group and they became Union J.
They said: "We're so happy to be a four piece. The group feels so right together, it feels like we've been together for years."
Jaymi said the show has been "a rollercoaster" but their mentor has helped them get through it.
He said: "Louis is the king of boybands and we're so grateful to have him as our mentor. Louis has been brilliant; he has made us become stronger as a group and has told us to work that much harder. He has already given us the boost that we needed."
Occupation: Customer Services Advisor
He overcame his nerves to reduce the audience to tears at his first audition with his rendition of The Rose by Bette Midler.
Chris has wanted to compete in the X Factor for years but this is the first time he has had the nerve to complete his application form thanks to a little encouragement from his grandmother Pat.
He said: "My nan kept going on at me so I decided to finally audition after all these years of being too scared to do it. People have said I'm not good enough and that I will embarrass myself, so I wanted to do this for myself, as I think I can do it."
Location: Harrow, London
Occupation: Admin assistant for his uncle's double glazing firm.
Woolly-hatted Adam has been playing the guitar since he was 15 and dreams of playing in front of a massive crowd at the Glastonbury Festival.
His musical heroes are the Kings of Leon.
He said: "I was born on 8/8/88. Other than it being quite unique I'm not sure what it means. I think the number eight in China is really lucky. Maybe next time I should go for the Chinese X Factor?"
Location: Romford, Essex
The teenager has just left school after her GCSEs and has put college on hold for a year while she takes part in The X Factor.
She has never had a singing lesson but loves to sing at home and in pubs and clubs near home.
She said: "I've known since I was a young girl that I've always wanted to enter The X Factor and as soon as I turned 16 I applied. It was also my granddad that made me enter. He told me before he passed away that I should follow my dream, so I knew straight away I had to enter."
Times Red (Staz, Scott and Luke)
Age: 21, 26 and 25
Location: London, Stirling and Essex
Occupation: Models and a promotions worker
Times Red have been friends for four years and write and play their own music. Scott plays guitar and sings, Staz sings and Luke beatboxes.
They said: "To be honest, winning is the furthest thing from our mind at the moment. All we are focusing on is each performance and doing the best that we can in every round."