Kate Middleton sparkled in a £3000 dress last night, during her first official public appearance with Prince William since their marriage.

The Duke and Duchess of Cambridge made a dazzling entrance at the black-tie Absolute Return For Kids Gala fundraiser at Kensington Palace.

The newlyweds were the centre of attention, and Kate, 29, stole the show in a stunning Jenny Packham gown, which she accessorised with £175 LK Bennet shoes and a clutch bag at the £10,000-a-head event.

William, 28, wore a traditional black tux, and the pair mingled for 45 minutes before the luxury dinner and fundraising auction.

It was a star-studded event, with more than 900 high-profile faces, including Oscar winner Colin Firth, actress Liz Hurley, Elizabeth Murdoch, the daughter of media tycoon Rupert Murdoch as well as Anish Kapoor, the sculptor who won the Turner Prize in 1991.

The celebrity crowd were treated to sets by DJ Mark Ronson and Kings of Leon.

Prince William got a standing ovation as he made a speech, announcing his new bride was joining himself and his brother Prince Harry in their charity foundation.

He told the wealthy guests: “This evening marks the start of a new joint initiative between Absolute Return for Kids and the Foundation of Prince William and Prince Harry and The Duchess of Cambridge.”

He then jokingly referred to it as “FPWPHATDC”.

He added: “I know that I am very fortunate. I have had a good education, a secure home and a loving and supportive family.

“So many young people do not have these advantages. I really believe that individuals can make a serious difference.

“My brother, Catherine and I hope to use our philanthropy as a catalyst for meaningful change.”

The royal brothers set up the foundation in 2009 to continue the legacy of Princess Diana.

Arkm, which helps disadvantaged children, was co-founded in 2002 by the financier Arpad Busson, who now acts as a trustee of the organisation.

A spokesman for the charity told the Daily Mail: “Over the past 10 years, Ark’s programmes in the UK, Southern Africa, eastern Europe and India have transformed the lives of more than 200,000 children.

“In tackling access to healthcare in sub-Saharan Africa, improving educational opportunities in the UK, US and India, and giving children the chance to live in a caring and nurturing environment in Eastern Europe, Ark is helping to overcome some of the most severe blights on children’s lives.”