For the entire season, judge Nicole Scherzinger sat on the judge's panel and served as a mentor to the Over 30s field on 'X Factor.' She dispensed advice, criticism and shed lots of tears as the most emotional judge AKA this reality talent show's version of Jennifer Lopez.

On tonight's elimination episode (Dec. 15), the Scherz stepped out from behind the judge's table and onto the stage to show the final four how it's done. The former Pussycat Doll (and 'Dancing With the Stars' Season 10 winner) performed 'Pretty' from her oft-delayed album 'Killer Love,' which is out in Europe but keeps getting bumped in the U.S. It was the worldwide live debut of the song.

We've gotta hand it to Nic, since she performed mid show, with her final remaining Over 30s team member Josh Krajcik unaware of his fate for the finals. She had to be a nervous wreck, concerned about whether or not Krajcik was moving on.

As usual, Nic looked sexalicious, ravishing and a lil tough in all black, with liquid leggings and leather fingerless gloves, with her hair slicked back into a tight, high ponytail. Her performance was robust and husky. It was as though she was channeling some of Krajcik's passion into her own performance. It wasn't a pretty performance -- pun intended -- but it certainly rocked.

The most hilarious moment of the entire season took place when Simon Cowell moved over into Scherzinger's vacant chair and critiqued her performance, using flowery language and metaphors to describe it, much the way the Scherz would speak about the contestants. Cowell said something about rainbows and waterfalls and it was utterly brilliant.

Watch Nicole Scherzinger Perform 'Pretty' on 'X Factor'