Prince William and Kate Middleton had a glamorous night out on Monday, hosting a reception for the U.K.- Africa Investment Summit at Buckingham Palace.

The Duke of Cambridge wore a navy suit with a red tie for the formal occasion. The Duchess of Cambridge was simply stunning in a long, sequined red number by Needle & Thread, as identified by People .

The $600 dress, which is now sold out, features a ruffled collar and long, beaded sleeves. Kate paired the gorgeous gown with a matching red clutch and heels, along with her trusty blowout hairstyle.

Princess Anne, Prince Edward and Sophie, Countess of Wessex, also attended the event alongside Kate and William.