The Princess of Wales welcomed diplomats to Buckingham Palace on Tuesday night, wearing Princess Margaret's favourite tiara and earrings that belonged to Queen Elizabeth II.
Kate joined the Prince of Wales, the King and the Queen Consort for the first Diplomatic Corps reception in three years as they greeted hundreds of guests at the glittering affair in London on Tuesday evening.
Meanwhile in the US, Harry and Meghan were in New York, preparing to accept the Ripple Of Hope Award for their racial justice and mental health work from Robert F Kennedy Human Rights (RFKHR) organisation.
The couple's tell-all show is just hours from being aired by Netflix on Thursday, and the royal family is bracing itself for bombshell revelations.
Kate, with her hair worn down, was dressed in a floor length scarlet Jenny Packham dress decorated in sequinned flower motifs, as well as her a blue Royal Victorian Order sash and the late Queen's Family Order, which sits on a yellow ribbon.
Her drop diamond earrings belonged to Queen Elizabeth II, while the Lotus Flower Tiara - also known as the Queen Mother's Papyrus Tiara - adorned her head.
Made of diamonds in fanned motifs crowned by floating diamond arches, it belonged to Princess Margaret.
Kate also wore it to the diplomatic reception at the Palace in 2013, and to her first state banquet in the UK in 2015 during the Chinese state visit.
The event at the Palace is the first Diplomatic Corps reception of the King's reign, and the monarch, his consort Camilla, eldest son and heir to the throne William and daughter-in-law Kate, a future queen, welcomed foreign ambassadors to the grand occasion in the royal residence's state rooms.
Camilla once again wore the late Queen's diamond and sapphire tiara and necklace, which she chose for the South African state banquet last month, and an Anna Valentine gown.
The late Queen was set to host the white tie gathering in March this year at Windsor Castle, but it was postponed due to Russian's invasion of Ukraine.
It is usually held every December, but there were no receptions in 2020 and 2021 due to the Covid pandemic.
The reception traditionally includes a buffet supper and dancing.