Kate Middleton wowed in a gray custom Erdem coat at the annual Commonwealth service at Westminster Abbey, London Monday. She was accompanied by her husband Prince William for the official engagement. The couple enjoyed a rare joint public appearance with Prince Harry.

Kate was dressed in an all-gray look for the Commonwealth service when the trio showed their support for Queen Elizabeth II. The 34-year-old royal’s coat is by British brand Erdem from its Pre-Fall 2015 collection. However, it is a bespoke version of the coat.

The coat featured long sleeves, single rounded edge collar and front button-down detailing. Kate’s coat had traces of Savile Row tailoring with lace being applied over a menswear-inspired fabric. This added a fresh and streamlined spin on her classic aesthetic.

The demure coat featured checked patterns and also an unusual lace pattern in a darker shade three quarters of the way down. The mother of two paired her stylish coat with matching suede clutch and gray round-toe high heels — suede Winona pumps by Rupert Sanderson. The princess accessorized with a pair of diamond drop earrings and her engagement ring.

The high-point of Kate’s ensemble was her gray wide brimmed hat by Knightsbridge-based milliner John Boyd. It had a wide gray ribbon around the brim. The unusually large hat with a slanting brim was made by the 90-year-old milliner, a new choice of milliner for the Duchess of Cambridge. It had a “Downton Abbey” vibe to it.

The milliner has been making hats since 1947. He was also a great favorite of Princess Diana, who wore his designs on several occasions. Meanwhile, the brunette beauty’s make-up was flawless as usual with smoky eyes and brown frosted lipstick. Her long locks were left loose in curls underneath her hat. 

William and Harry meanwhile looked dapper in navy suits and trousers combo. The brothers completed their look in black lace-up shoes. The royals celebrated the service that is traditionally held on the second Monday of March every year. It recognizes the 53 countries and its people that make up the Commonwealth.