Simon Cowell will be hoping for X Factor glory as he becomes the mentor to the girls for the first time.
Head judge Simon has mentored the overs category for the last two years on the ITV talent show.
Former Pussycat Dolls member Nicole Scherzinger will mentor the boys, Louis Walsh will mentor the groups and Sharon Osbourne will mentor the overs.
Sharon, who returned to the judging panel this year, won the show in 2013 with the same category when Sam Bailey was named winner.
The mentoring categories were announced at the end of the Bootcamp episode of the show.
More than 100 acts took to the stage at north London venue Alexandra Palace in a bid to make it through to the six-chair challenge.
Former X Factor participants Gifty Agyeman, 20, also known as Gifty Louise, and Anelisa Lamola, 26, are both through to the next round.
Gifty said: "When I saw Simon walk through there, honestly my head just exploded. My heart was beating just, like, yes."
Samantha Atkinson, 32, and James Wilson, 34, are both through to Sharon's six-chair challenge in the overs category.
Viewers saw James disappear moments before he was due to perform at Bootcamp, as the pressure of the show became too much for him.
The carpenter, who has dyslexia, explained: "I found out I had dyslexia when I was six or seven. I struggle with my reading and writing, it's difficult for me because it's all about reading the lyrics."
Couple Tom, 24, and Laura, 29, from Liverpool, will also compete in the overs six-chair challenge after raising their game during their audition.
Beforehand a nervous Laura admitted: "I'm afraid I'm going to let Tom down. I have to prove to Simon I deserve to be on that stage as much as Tom."
Also through to the next round is rapper Honey G, who said it was all "going to go down at Wembley Arena, it's going to kick off left, right and centre. This is the sickest thing that's ever happened to me".
The boys' category may be the one to watch this year, with strong contenders such as Matt Terry, 23, whose nan came in to hug Simon during her grandson's audition.
Nicole's group were in good spirits as she addressed them for the first time, saying: "I hope you guys are ready to work, I wish I came in here with a whip," to which someone cheekily replied: "So do we."
Next week the contestants will take to the stage at Wembley's SSE Arena as the six-chair challenge kicks off.
The hopefuls will sing in front of a live audience as the judges whittle their groups down to just six people, who they will take through with them to the Judges' Houses round.