The 38-year-old former All Saints singer and Sinitta were pictured with their arms around each other as they prepared to jet off and join Walsh in the South of France's swish St Tropez region.
It's currently being reported that Sinitta, who has previously joined former boyfriend Simon Cowell at Judges' Houses, has also been helping Walsh whittle down his category.
The Daily Star has claimed that the 49-year-old 'So Macho' singer even revealed herself to Walsh, Appleton and the X Factor hopefuls wearing a fake baby bump to announce "who's the daddy?", presumably in reference to the recent news that Cowell is expecting his first child with Lauren Silverman.
Other star guests set for Judges' Houses with remaining X Factor mentors Nicole Scherzinger, Gary Barlow and Sharon Osbourne are yet to be confirmed.
Barlow recently revealed to Digital Spy that Robbie Williams would not be helping him decide who will be going through to the Live Shows.
Appleton was recently reported to have split up with her husband, Beady Eye frontman Liam Gallagher.
See the contestants who appeared on the first episode of The X Factor's 10th series below: