The Duchess of Cambridge stepped out in red - the colour of the Chinese national flag - for her inaugural Buckingham Palace state banquet.
Kate also chose to wear the delicate Lotus Flower Tiara for her first glittering sit down dinner in the UK in honour of a world leader.
Her sparkling, floor length bespoke red gown was by one of her favourite designers Jenny Packham.
She borrowed the tiara - also known as the Papyrus Tiara - from the Queen after first wearing it two years ago to a diplomatic reception in 2013.
Made of diamonds in fanned motifs crowned by floating diamond arches, the tiara was owned by the Queen Mother, who used to wear it low on her forehead, and was later given to Princess Margaret.
It is only the third time Kate has been seen in a tiara. She wore the Cartier Halo tiara for her wedding in 2011.
Four-and-a-half years after she became an HRH, Kate made her first appearance at what is considered a staple royal duty - dining in the opulent palace ballroom with 170 guests in honour of a visiting president.
It was also the Duke of Cambridge's first state banquet in the UK.
Kate joined the Royal Procession into the Ballroom, following behind William who walked with Caroline Welby - the wife of the Archbishop of Canterbury.
Kate walked alongside Wang Huning, one of the Communist Party of China's top leaders.
She was seated in the most prominent position for a female member of the royal family after the Queen - on the President's right while the monarch, as is custom, sat on Mr Xi's left.
As the wife of the second in line to throne, Kate takes William's status when she accompanies him, so outranks blood princesses such as the Princess Royal, who was also present.
On Kate's right sat Mr Huning.