The reality star looked as polished as ever in a knee-length peplum dress, £128 by Three Floor, which featured faux leather panels and a delicate lace overlay.
And she's not the only one loving Three Floor's elegant frocks - Lucy Mecklenburgh previously wowed in the brand's cobalt blue dress. They must be a celeb favourite!
Despite her feminine attire, Rosie unleashed her sultry side with sexy caged heels, £59, by JustFab.co.uk, and a gold studded clutch, £49. also by JustFab.co.uk.
The Made In Chelsea star clearly has a killer instinct for fashion, so it's a good thing we've already quizzed her on her summer style secrets - check them out here!
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