Cressida Bonas joined Princess Beatrice and her boyfriend Dave Clarke at Zoe Stewart and Jake Warren's wedding in Chelsea on Saturday.
The royal connection? Jake was one of Princess Diana's godchildren and is a close friend of Princes William and Harry. Zoe is also pals with Zara Phillips.
The dresscode? Smart, winter style for the service and cocktail dresses for later, as modelled by Cressida and Beatrice. However - guess who's style was edgier? (Hint: look for the flower headband.)
However - our favourite thing about Cressida's winter wedding outfit? The floral crown. She's not quite at tiara level just yet, but everyone knows that a silk flower hairband is so much more chic anyway.
Sounds like the guests had a good old knees-up at the reception.
Love Beatrice's vintage-inspired hat? Here's a few more of her brilliant (and bad) hat moments:
Love Cressida's flowers? Here's how to make your own: