As fashion month draws to an end, there's one thing we're certain of: One of our favourite hairstyles is making a comeback. Karl Lagerfeld sent models down the Chanel runway with messy topknots. Yep, the dolly bun is back in fashion. We know that you're probably already perfecting a topknot on Sundays, but Chanel proves you can wear it with a smart shirt, while Olivia Palermo and Bella Hadid know it can soften a supercharged outfit. Pulling this gallery together, we're sold, and this is potentially the only hairstyle we'll be wearing this summer—it's just so easy to do. Not sure how to perfect the look? Click here to find out how to do a messy bun at home.