Poppy Delevingne worries about looking ''too out-there'' at big events.

The 32-year-old model-and-actress likes to play it safe if she's unsure of the dress code for a particular function and goes to her classic little black dress with bold shoes and make-up.

Speaking to Vogue Australia, she said: ''If I am very unsure of a dress code, I like to keep it very, very simple. I think it's always a little scary if you go too out-there.

''For me, what I'll do is maybe a little black dress with a statement heel and a red lip. Nothing too out-there that's going to get me into trouble.''

The 'Kingsman: The Golden Circle' actress is no stranger to attending prestigious events and was recently a guest at the royal wedding of Princess Eugenie and Jack Brooksbank on October 12, at Windsor Castle, and thought that the bride was ''more beautiful than she'd ever seen her''.

She said: ''It was beautiful - the whole thing was beautiful, she was more beautiful than I've ever seen her, just the most glowing bride. It was really a weekend to remember.''

The star wore a pale blue Oscar De La Renta dress and coat paired with a Victoria Grant hat adorned with vegan feathers to the event, and Poppy explained that sustainable fashion is something she's particularly passionate about.

She said: ''I think sustainability is something that is so, so, important especially now and it's impossible to ignore what's going on in the world, and we all have our part to say.

''I do think we've all got a huge responsibility to now wear more ethical and sustainable fashion and so taking these strong stances, I think it's exciting.''