The red-haired starlet stepped out at Wembley Arena for The X Factor final to support her act Sam Bailey, who was competing against Nicholas McDonald.
And with such an important night ahead, it was only fair Sharon pulled out all the fashion stops!
The judge looked absolutely stunning as she made her way across the stage in a floor-skimming red gown by Zuhair Murad.
The gorgeous frock boasted sheer long sleeves and a figure-hugging silhouette, adorned with an intricate bejewelled floral pattern.
But unfortunately for Shazza we've spotted the dress before, on none other than former X Factor judge Cheryl Cole!
The former Girls Aloud singer wore the lavish gown to a screening of Jimmy P. Psychotherapy of Plains Indian at Cannes Film Festival earlier this year (18 May).
Cheryl slicked back her brunette locks and even matched her frock to her peepers, sweeping burgundy eyeshadow along her lower lashline. She opted for minimal jewellery with diamond stud earrings and a statement ring.
Sharon, on the other hand, styled her fiery tresses in a whimsical updo to show off her red beaded earrings, before adding a touch of rouge on her nails and lips.
Sharon looked positively thrilled and more than a little tearful as she watched Sam take The X Factor crown, later tweeting: "I am so blessed to have been a tiny part of @SamBaileyREAL's victory tonight on @TheXFactor. Thank you. #XFactorFinal."
She even invited Sam's whole family for Christmas dinner at the Osbourne's while live on The Xtra Factor. Now that's gotta be a meal to remember, right?
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The X Factor final in pictures:
Copyright: Rex Features Tom Dymond / Thames