Duchess Kate Middleton took her latest red carpet appearance to the next level, wowing in a cream-colored gown with a thigh-high slit at a very private and intimate dinner at Claridge's hotel in Mayfair, London, last night. 

OK! GALLERY: KATE MIDDLETON & PRINCE WILLIAM CELEBRATETHEIR WEDDING ANNIVERSARY! CHECK OUT THEIR YEAR IN PHOTOS! 

Accompanied by her husband, Prince William, the Duchess of Cambridge was gorgeous and glowing as she walked into the event, which was set up for a meeting of the Thirty Club, which boasts some of the most powerful men and women in advertising and the media as members.

OK! GALLERY: KATE MIDDLETON & PRINCE WILLIAM DAZZLE AT THE AFRICAN CATS PREMIERE IN LONDON 

Kate, as well as a tuxedo-clad Wills, was dressed to impress in her stunning gown and sparkling Jimmy Choo stilettos, which she accessorized with a metallic clutch.