This year on the red carpet: Sienna Miller, Blake Lively, Rihanna, Lily James

Sienna Miller proved a stunning dress needn’t be splashy at the Cannes screening of La Glace et Le Ciel in May. 

With its leather top and pleated skirt, this Gucci dress united two of Spring/Summer 2015’s biggest trends.

Blake Lively’s first red-carpet outing for The Age of Adaline was in New York in April. She set the tone for a particularly glamorous press tour in this leather and lace Monique Lhuillier gown. Notwithstanding the koi fish-shaped clutch, this is my favourite look of 2015.

It was a gloves-off, gowns-on battle to be the best dressed guest at July’s Met Gala ball. Rihanna was a knockout in a Guo Pei Couture design.

Lily James promoted Disney’s Cinderella in a parade of princess gowns last Spring. She wore a crystal-studded Elie Saab dress and custom-made “glass slippers” by Christian Louboutin for the film’s Hollywood premiere in March.