The Made in Chelsea star went all Great Gatsby on us at the star studded event and blew everyone away in the Julian Macdonald mini dress dripping in beads and sequins, which also boasted a deep V-shaped neckline, tassels and an art-deco-inspired chevron design.
We're seriously lusting after it for all of those festive parties...
Rosie and her perfect pins teamed spangly, traffic stopping frock with Lulu Guinness' trademark lips clutch, a pair of criss-cross strappy sandals from Dune and a super-cute pink stone ear cuff from her own jewellery collection - which you can snap up right here.
With her honey-hued locks styled in sumptuous waves Rosie looked every inch the superstar and even pipped guests Cheryl Fernandez-Versini and Rosie Huntington-Whiteley to the post as best dressed.
Yeah, we went there!
Rosie paid a visit to make-up maestro Helena Kastensson at NARS for her old-school Hollywood glamour beauty look which consisted of a matte red lip to match her snappy little bag, a smouldering smoky eye and possibly the best highlight we've ever laid eyes on.
The reality stunner mingled with the likes of Lady Gaga, David and Victoria Beckham and X Factor judge Rita Ora to name but a few celebs at the city bash while fans sat down to catch the beginning of latest MIC series on E4.
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