The TOWIE star took a break from filming new workouts for her Results With Lucy website to once again nail effortless summer elegance in her pretty outfit, which was belted at the waist to highlight her svelte frame.
She kept her accessories minimal and her make-up natural, letting her vibrant outfit do all the talking.
Lucy was also sporting a glowing tan. Has she been sunbathing in the garden while the UK laps up the heatwave?
She attended the star-studded bash with TOWIE cast mates Jessica Wright and Samantha Faiers, and tweeted at the start of the night she was feeling a bit tipsy.
"Something's telling me tonight is going to get messy!!! ;-)" she joked.
Well, we wish we looked as good as her when we're leaving the venue after a big night out!
The 21-year-old has spent the week filming new workouts for her exercise and nutrition website Results With Lucy, which aims to make her healthy living lifestyle accessible to fans – and showed off the results of all that hard work by posting a picture of herself sporting a crop top on set earlier this week.
She's also been brushing up on her kitchen skills so she can share her eating regime with subscribers.
On 16 July she tweeted: "Had soo much fun learning how to cook today! Coming soon my own healthy eating diet plans & video cooking lessons."
May we suggest next on the list is a how-to guide on her fab fashion!
Check out who else was at the ITV summer party in our gallery:
Copyright: Rex Features Rotello
Watch Lucy introduce her fitness website: