The brunette wowed in an unusual LBD featuring cheeky sheer panel cut outs as she joined a host of stars at the Claire's Halloween Party at Sketch on Tuesday night (22 October).
Jessica teamed her dress with sky high black heels and a gorgeous colour pop red clutch bag. Beauty-wise, she kept her long hair loose and styled it in her trademark bouncy glossy waves, and went for mega-watt lashes, a smoky eye and statement lip.
We imagine her winter tan came courtesy of her own lush-smelling tanning range, Fruity Tans, which she launched earlier this year.
A perfect look for those wanting a bit of Halloween chic this year.
Jessica had company in the form of younger sister Natalya, who celebrated her 13th birthday earlier this year, and also went for an all-black look. Mum Carol and grandmother Nanny Pat were also there.
During the evening, Jessica rubbed shoulders with a rather familiar face: last year's X Factor winner James Arthur. And it's fair to say Jess appears to be a big fan!
Tweeting a photo of the pair together, she wrote: "Me and the legend that is James Arthur. Remember to download this guy's debut single." (James is currently promoting track 'You're Nobody 'Till Somebody Loves You', a follow-up to his XF winner's single 'Impossible'.)
James wasn't the only X Factor star Jess and Natalya met either: they later cosied up to Josh and Jaymi from Union J. "Love these boys," wrote Jessica alongside a pic. "They're smashing it. Love their new song."
Natalya was equally impressed, tweeting: "Union J are just even better in real life."
Wish we'd had a big sister who took us to cool events when we were 13!