The judge posed alongside her ex-boyfriend Lewis Hamilton, who stood out in a silver blazer.
The pair were in an on-off relationship with seven years before calling it quits for good in 2015.
Nicole’s appearance at the event comes just two days after she wrapped up her judging stint on the X Factor: Celebrity.
The star’s act Jenny Ryan impressed viewers with her vocals, but missed out on the win to Megan McKenna, who was mentored by Louis Walsh.
Despite her act losing, Nicole stole the show with her raunchy performance with her fellow Pussycat Dolls.
The band belted out vocals to some of their greatest hits, but received over 400 complaints about their racy outfits.