Cheryl Cole - who was given her big break on TV talent show Popstars: The Rivals - will tell the X Factor hopefuls she can sympathise because she has been in their position.
The Girls Aloud star says: "I've been there and I have been here so I know how you are all feeling, I am just excited to see what you have got. [I] think it's going to be amazing and I wish you the best of luck from the bottom of my heart."
Other guest mentors include Tinie Tempah, who teams up with Tulisa Contostavlos, Ne-Yo who accompanies Nicole Scherzinger and Sharon Osbourne who is the sidekick to Louis Walsh.
Former X Factor judge Cheryl Cole will be back on the show tonight, almost two years after her departure.
Cole will return as a guest mentor, helping Gary Barlow put his acts from the older "overs" category through their paces during the judges' houses stage of the ITV1 talent show.
She bowed out from the UK X Factor after the 2010 series to take up a short-lived place on the panel for the US version of the show.
Cheryl Cole said she was "absolutely fine" despite her arm being in a sling after she was injured in a car crash in LA with Will.i.am.Read the full story ›
Pop stars Cheryl Cole and Will.i.am were left with whiplash after a minor car accident today.Read the full story ›
Cheryl Cole has given the strongest hint yet that Girls Aloud will be getting back together to celebrate the group's 10th birthday.Read the full story ›
Cheryl Cole has said she had to stop Will.i.am tweeting while they were standing behind the Queen at the end of the Jubilee concert.
The singer told Graham Norton she stepped in after the avid tweeter pulled out his phone.
She said: "I actually had to warn him as we walked on to the stage. He had the phone at the ready. I'm not joking, I had to say to him 'Put that phone away right now before I kill you'."
The Black Eyed Peas star famously tweeted while running with the Olympic torch and was seen using his phone while filming The Voice.
Cheryl Cole said she has got her "voice back" after she started taking on her critics on Twitter.Read the full story ›
Gary Barlow star sang a duet with Cheryl Cole as part of the Queen's Diamond Jubilee concert in London.
Former ITV1 X Factor judge Cheryl Cole has said she does not "even think" about the show's supremo Simon Cowell any more.Read the full story ›
Cheryl Cole dazzled the red carpet tonight at the premiere of her first Hollywood movie. The Girls Aloud singer, dressed in an off-white Victoria Beckham gown, joined actress Cameron Diaz at London's BFI IMAX cinema for the screening of pregnancy comedy What To Expect When You're Expecting.
Cole - who was dramatically axed from Simon Cowell's US version of The X Factor - makes her big screen debut in the film, playing a TV talent show judge.