The 'Made for Lovin' You' singer has stepped in as the guest fourth judge for the Glasgow auditions this week, where audience members are said to have reacted positively to her appearance.
During her time on the show, she has openly flirted with Gary Barlow, stood up for Tulisa Contostavlos after a hopeful teased her over her sex tape scandal and took to the stage to take a look at a contestant's kilt close up.
Barlow tweeted this week: "Well done Anastacia for being a great guest judge yesterday."
Nicole Scherzinger is highly tipped to become the next permanent judge, but has yet to sign a full deal.
"Everything is in place to sign Nicole but Anastacia was incredible," a source told The Sun.
"She had such great chemistry with the others. Nicole has been good in the past but she hasn't worked with anyone on this panel before except Louis, so who knows how she will do?
"Nothing is certain on The X Factor - things change down to the wire."
In pictures - Anastacia at the X Factor Glasgow auditions:
Copyright: Rex Features Ken Mckay/Thames