Kate Middleton wears a long red double-breasted coat with a peak lapel and flap pockets. It is a custom piece from Alexander McQueen.
The coat combines elements from coats that company offers in their ready-to-wear collections (past and present) –
The black coat is the closest match design-wise. It features two sets of buttons and the same seam detailing at the waist. Obviously, Kate has had the drape element removed.
The Princess has worn the red coat on five public occasions to date. To launch the ‘Hold Still’ outdoor photography exhibition at Waterloo, London, in October 2020. During a visit to Cardiff for the Royal Train tour in December 2020. At the England v Papua New Guinea rugby game in November 2022 (pictured below), for the ‘Together At Christmas’ Carol Service in December 2024 and recently, during a visit to Wales in February 2025 (pictured above).
She owns the coat in green and brown too:
Note: the image below shows a grey Alexander McQueen coat that I (badly) edited to look red in Photoshop. The design of the coat was the closest match to that worn by the Princess.