The Made in Chelsea star pulled out all the style stops with a pair of fitted trousers in an eye-catching orange, and we love how she teamed them with a sheer white shirt for a simple and chic look.
Ever the perfectionist, Louise even managed to find just the right shade of nail colour to match her outfit on Wednesday night (4 September).
Louise was joined by friends Millie Mackintosh and Ashley James at the star-studded bash, who later went on to party the night away at the opening of Millie's fiancé Professor Green's new club INK in Leicester Square.
For Louise, last night was a break from filming the new series of Made in Chelsea.
The previous evening, filming for the E4 show ran late, meaning Louise missed out on a scheduled appearance at the Jeans For Genes Day 2013 party. "Absolutely gutted to have missed @JeansforGenes event :-( !!" she wrote. "Had to film Made in Chelsea all day... Big projects to come though!"