The former Pussycat Doll looked sizzling in a sexy leather mini dress as she left the exclusive Nobu restaurant in central London on Sunday night (27 October).
Nicole looked in high spirits as she made a quick dash to her car, sheltered by an umbrella to avoid the stormy weather in the capital.
Earlier in the evening, however, she'd been in a far less happy mood, after her act Hannah had to sing for survival on the third live results show.
Nicole and many viewers were left stunned when Hannah, 19, fell into the bottom two despite the judges raving about her Movies Week performance of 'Skyfall' by Adele.
Gary Barlow told a visibly upset Hannah that he reckoned viewers thought she was so good she'd be automatically safe and implored the audience to always vote for their favourite and not assume anything.
Hannah was up against Gary's group Miss Dynamix, who were revealed as the act with the lowest number of votes following Saturday's flash vote.
In the end, it was Miss Dynamix who left the competition, but they told Dermot O'Leary they were proud to have left on a strong sing off performance.
Watch Hannah's performance of 'Skyfall' below:
Nicole, meanwhile, took to Twitter after the results show had wrapped to urge fans to vote for Hannah next week and not presume she is safe.
She tweeted: "Pls make sure to vote for @HannahBMusic on @TheXFactor She is the truth! "A Phoenix rising from the ashes"
It was definitely a stressful night for Nicole, but luckily she had her best friend in town to help her. Nicole tweeted a picture of the duo together last night, adding the caption: "So happy to have my best friend Katie w/me here in London for support n good times:)."
Next week's X Factor will have disco theme and feature performances by Taylor Swift and Little Mix.