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.)
Cressida's style is unique, but it's definitely not boring. Prince Harry's girlfriend arrived for the wedding in a leather and fur coat and peep-toe heels. Although most of her dress was hidden, that flash of blue and white print suggests it was pretty jazzy too.
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.
As for Princess B, she stuck to her classic wedding style in a blue coat, patent heels and a matching tan clutch. No hairband, but her mustard pillbox hat looked elegant.
Cressida and Beatrice weren't the only familiar faces to attend the service either. The Daily Mail reports that Mumford & Sons lead singer Marcus was Warren's usher. He even sung for the newlyweds inside the church. Sweet!
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: