Spice Girl Geri Halliwell is the first guest X Factor judge to stand in for Dannii Minogue.
She joins Cheryl Cole, Simon Cowell and Louis Walsh on Wednesday for day one of the auditions in Glasgow.
Dannii is taking time off to have her baby, but she'll be returning to the panel when the talent show gets to the live show stages.
Geri's only confirmed for one day so far, but she might be returning in the future.
Dannii will be back for the live show stages
It's not the first time Geri has worked with the judges.
She was on the panel for Popstars: The Rivals, the programme that created Cheryl's band Girls Aloud back in 2002. Louis Walsh was also a judge on that show!
We don't yet know who else will be stepping in as a guest judge this series.
Earlier this week, former Blue Peter presenter Konnie Huq was announced as the new presenter of The Xtra Factor.