The boyband, who finished third on the show in 2010, will act as backstage mentors, giving advice to the contestants, The Mirror reports.
Simon Cowell and producers hope their appearance, which will also include an interview with host Dermot O'Leary, will boost ratings to help The X Factor beat Strictly Come Dancing.
"X Factor is where it all began for One Direction so it makes sense for them to come back and perform," a source said.
"Making an appearance on Saturday means they are the secret weapon that could tip the balance in the ratings war. They've also said they'll act like extra mentors backstage for this first weekend.
"Strictly have got some big names, but nothing as big as One Direction. It is going to be a colourful and action-packed first show and we are confident everyone will be talking about The X Factor after Saturday night."
One Direction previously ruled out judging roles on The X Factor.
Leona Lewis will perform her new single 'Trouble' on Sunday's Results show, while One Direction are expected to perform 'Live While We're Young' at a later date.
Watch the band's video for 'Live While We're Young' below: