Catherine joined Prince William, making her spectacular debut for the royal occasion.
The much-anticipated banquet was held at Buckingham Palace, in honour of the Chinese President Mr Xi Jinping, but the evening’s highlight was Princess Charlotte and Prince George’s mum's first big glamorous night out following the end of her maternity leave.
Kate didn't disappoint, wearing a glorious gown by her favourite designer, Jenny Packham. She paid tribute to her guests' home country by wearing a beautiful red dress - not only the colour of China's flag, but the colour also symbolises good fortune and joy.
But it was her dazzling tiara that had everyone talking on the night. Atop her loose, low bun was the royal family's gorgeous Papyrus/Lotus Flower tiara.
It was the Queen Mother's, and a personal favourite for Princess Margaret.
The delicate diamond headpiece was made from a necklace given to the Queen Mother as a wedding present in 1923.
Author of the Queen's Jewels, Leslie Field, described the tiara as, "a beautiful pearl and diamond piece. It's very much in the twenties style and probably quite lightweight and comfortable to wear."
Until now, we’ve only seen the Duchess wear a crown twice. She wore the Lotus tiara once before at a diplomatic reception in 2013, and she most famously first wore the Cartier Halo tiara at her 2011 wedding.
Completing the 33-year-old’s regal look were the perfect accessories – matching diamond earrings and bracelet. The bracelet on the Duchess' left wrist was loaned to her by the Queen, who was gifted with the jewels on her wedding day.
The Buckingham Palace banquet was hosted by the Queen and Prince Philip for the Chinese President and his wife Peng Liyuan, who are currently on a four-day state visit to the UK.
Included on the 170-strong guest list was British Prime Minister David Cameron, Prince Andrew, Prince Edward and Princess Anne.
Prince William's father, Prince Charles and wife Camilla were mysteriously absent, instead enjoying an afternoon tea at Clarence House with the Asian dignitaries.
“Your visit to the UK marks a milestone in this unprecedented year of co-operation and friendship between the UK and China. We have much reason to celebrate the dynamic, growing economic relationship between our countries,” the Queen said at the beginning of the dinner.
The extravagant meal was served at a horseshoe-shaped table adorned with colourful floral displays, which included Clematis - flowers native to China. The room was lit up with more than 100 candles in silver-gilt candelabra, many from George IV’s reign.
During her speech, Queen Elizabeth recalled one of her most treasured memories, a visit to China with her husband.
"Prince Philip and I recall with great fondness our visit to China almost 30 years ago, where we were privileged to experience your country’s rich history and culture, including the Great Wall, the Forbidden City and the Terracotta Warriors: all unforgettable memories of China’s ancient civilisation."
Her Majesty concluded her speech, requesting the room to raise their glasses and declaring, "Ladies and Gentlemen, I ask you to rise and drink a toast to the President and Madame Peng and to the people of China."
China's leader was given a ceremonial welcome at Horse Guards Parade by the Queen and Prince Philip.
The royals pulled out all the stops for the president who got to travel with the Queen to Buckingham Palace in the Diamond Jubilee State Coach for lunch.
The visit has been described as the start of a "golden era" of relations.
The Chinese are said to be huge fans of the royals. Prince William visited the country back in February of this year, where he was widely praised for handling his tour with tact and diplomacy.