Nicole has become a fan favourite during her three previous series on the ITV talent contest, and its other stars appear to think she's just as sch-amazing as viewers do.
Speaking to the BBC at a press launch for the latest run yesterday, Dermot claimed that the 'Poison' singer is the most hands-on judge.
"If I was a contestant I'd probably want Nicole, because she probably works hardest and is most focused," he commented.
Louis also put his competition with the judges aside to single her out as the top panellist.
"Nicole is the best judge I've ever worked with. She works so hard behind the scenes," the Irishman added.
As for Nicole herself, she says she gives total commitment to whatever she puts her mind to.
"Everything I do, whether it's recording a song, a workout or this, I put 110% percent because I care," she said.
"I love my job as a mentor so my job is to bring out the absolute best in these people as artists and as humans."
Meanwhile, Nicole has revealed she still keeps in touch with Jahmene Douglas, James Arthur and Rylan Clark-Neal - the three boys she backed on her first series of the show in 2012.
Speaking about Rylan specifically, she said: "We've not missed a beat - we still WhatsApp every single day."
The X Factor returns to ITV on Saturday and Sunday at 8.00pm.