Stephanie, who was voted off the ITV singing show after the second week of the live shows, rubbed shoulders with celebrities at the party, which was held at the Dirty Martini cocktail bar.
Former Luminites singer Stephanie looked effortlessly glam as she rocked a black mini dress with a contrasting white skirt.
Keeping it simple, the songstress teamed her outfit with gold strappy heels and accessorised with an embellished black clutch bag.
Stephanie first rose to fame in the Luminites after reaching the live shows of the seventh series of Britain's Got Talent in 2013. But after the band split, she auditioned as a solo singer on the current series of The X Factor.
Mentored by Cheryl Fernandez-Versini, Stephanie reached the live shows and performed to millions of viewers for two weeks before being voted off.
Stephanie is still hoping to pursue her solo dreams, and told Reveal after her exit: "I think there's amazing opportunities that have come along for me to be by myself."
Stephanie has still been watching the singing competition too, and told fans over the weekend after Jake Quickenden got voted off: "Gutted for @JakeQuickenden knew how much it meant to him. He's gonna do amazing!"
What do you think of Stephanie's monochrome dress? Tell us below, as the best comment from across the website each week wins £50!
Reveal is now on Google Plus! Join us here for the latest pictures, fashion and celebrity news!