They include a prison officer desperate to break out into the music business and mum-of-two Sam Bailey, 36 from Leicester, who weeps at her audition after singing Listen by Beyonce when judge Nicole Scherzinger tells her: "That's exactly how that song is supposed to be sung".
The show also marks the return of Sharon Osbourne to the judging panel five years after she quit amid rumours of tension with fellow judge Dannii Minogue.
The wife of rocker Ozzy Osbourne, who is replacing Tulisa Contostavlos, is joined on the panel by Gary Barlow and Louis Walsh.
But she is less than impressed by Fil Henley, a would-be rocker who comes to the audition armed with a guitar and sandwiches his mum made for him.
The 30-year-old, from Maidenhead, performs his own take on Robbie Williams' Let Me Entertain You, but Osbourne is more interested in his mullet hairstyle which she describes as "business at the front, party at the back".
Sharon has said there will be no personality clashes on the judging panel this year because the judges "actually like each other".
The fiery star, said: "It's way beyond that. We have respect for each other, we actually like each other".
She added: "There's no him or her, just mutual respect."
Show supremo Simon Cowell made a brief appearance at a press conference launch in London's Mayfair Hotel.
He said: "Once again I feel like a very proud daddy."
The show, which will be hosted by Dermot O'Leary, with Caroline Flack and newcomer Matt Richardson on spin-off show The Xtra Factor, returns to ITV tonight. There is a second episode of the show, hosted by Dermot O' Leary, tomorrow night.