Kate Middleton and Prince William Leave the Kids at Home For a Royal Reception in London

Kate Middleton arrived in style at the annual evening reception for members of the Diplomatic Corps at Buckingham Palace in London on Thursday. The 34-year-old royal, who was joined by Prince William, Prince Charles, Camilla, duchess of Cornwall, Prince Philip, and Queen Elizabeth, looked stunning in a red Jenny Packham gown and the Cambridge Lover's Knot Tiara, which was given to the late Princess Diana by the queen as a wedding present back in 1981. Just hours before Kate and Will's big event, it was announced that Kate's younger sister, Pippa Middleton, had officially set her wedding date; the 33-year-old will marry her fiancé, financier James Matthews, on May 20, 2017 at the St. Mark's Englefield in Berkshire, UK, and Kate and Will's kids, Prince George and Princess Charlotte, will reportedly act as "a page boy and flower girl," respectively.

Last we saw Kate and Will, it was for a decidedly less celebratory event; the couple attended a memorial service for the duke of Westminster, Gerald Grosvenor, late last month, but before that she made a number of lovely public appearances, including having a tea party with students at London's Natural History Museum and representing the royal family at the Recovery Street Film Festival.