The British beauty is the face of the French brand's latest campaign.
Alex Chung hosted a fancy dinner with Longchamp in New York last night.
The model and TV presenter invited a number of VIP guests along to the gathering including stylist Cleo Wade and sophisticated socialite Atlanta De Cadenet.
True to form, Alexa - who has now been working with Longchamp for four seasons - chose a suitably stylish ensemble for the decadent occasion.
She stepped out wearing a short shimmery dress that was cut with a loose fit and had a thigh-skimming hemline. The baggy design also featured black ribbons that she tied into a halterneck.
Alexa complemented her sassy mini - and added a couple of inches to her already long and lean legs - with a pair of towering pointed snakeskin heels.
She carted her essentials about in a deep purple clutch with a shiny gold clasp, giving us a major case of bag envy.
Naturally, Alexa totally won us over with her choice of hairstyle too. The British style icon teased her impossibly glossy and choppy short layers into tousled waves.
Before heading to the star-studded get together, Alexa shared a close-up shot of her summery ombré 'do on Instagram, saying: '1970 by Diego hair wiz make up by @kristingallegos.'
The event comes after Alexa was signed up to promote the luxury brand's bold and bright SS15 campaign - something she was clearly thrilled about.
'I love bags, I love France, I love Longchamp,' she said earlier this year when speaking of the partnership.
In Longchamp's latest advert, the 31-year-old is seen strutting along confidently in a short coral dress. She accessorises her summery outfit with a number of different Le Pliage Héritage bags in shades including neon yellow, nude and electric blue.
The promo was shot in southern French city of Marseille.
