Royals Future Queen Kate Middleton Helps Queen Elizabeth Host Leaders at Palace Without Prince William Kate Middleton joins the Queen and her father-in-law Prince Charles to help entertain NATO leaders at Buckingham Palace By Simon Perry Published on December 3, 2019 01:33 PM Share Tweet Pin Email Kate Middleton is continuing to cement her role as future queen as she helps her grandmother-in-law Queen Elizabeth entertain leaders from around the world, including President Donald Trump, on Tuesday evening. Kate, 37, is without husband Prince William, who is currently on a royal tour in Kuwait and Oman, but she joins other senior members of the royal family for the Buckingham Palace reception, which marks 70 years of NATO. The royal mom, who opted for a bright green ensemble for the occasion, was spotted on her way to the palace reception after leaving her Kensington Palace home. Multiple sources tell PEOPLE that they have observed a growing confidence in Princess Kate, 37. While raising her three children with Prince William, she has found passion and purpose in helping mothers and children everywhere. “She is finding her voice,” says a well-placed palace source. Kate Middleton Has Been Secretly Working in a Maternity Unit in London Prince Charles and his wife Camilla, Duchess of Cornwall will also be alongside the Queen, 93, to formally receive the NATO leaders and their partners before a formal photograph of the royals will be taken with the various heads of state and government. YUI MOK/POOL/AFP via Getty Kate Middleton. Donald & Melania Trump Attend Queen Elizabeth’s Palace Reception — Without the Trump Kids, Who Came Last Time Kate Middleton arrives at palace reception. The Queen, Kate and Charles and Camilla will also be joined by the Queen’s daughter Princess Anne, the Duke and Duchess of Gloucester and Princess Alexandra to help welcome guests in the State Rooms of Buckingham Palace. Queen Elizabeth. Notably absent from the reception is Prince Andrew, 59, who has stepped back from public life in the wake of his bombshell interview about his friendship with convicted sex offender Jeffrey Epstein. Chancellor of Germany Angela Merkel talks to Queen Elizabeth at a reception for NATO leaders at Buckingham Palace. Queen Elizabeth and NATO leaders. YUI MOK/POOL/AFP via Getty Two royal family members who are also not in attendance are Meghan Markle and Prince Harry. The Duke and Duchess of Sussex are missing the event as it falls during their “family time” off from royal duties. The new parents previously revealed that they would be taking about six weeks off towards the end of the year amid their concerns that the intense scrutiny they’ve faced has been tough on the couple. Kate Middleton. YUI MOK/POOL/AFP via Getty Meghan Markle Is ‘Very Aware That Kate Will Be Queen’ — But They Are ‘Pitted Against Each Other’ Meghan, 38, and Harry, 35, are also planning to skip the annual holiday festivities at Sandringham — including their public walk to church on Christmas morning. Princess Anne. Yui Mok - WPA Pool/Getty From left: First Lady Melania Trump and President Donald Trump at Buckingham Palace on Tuesday. Dan Kitwood/Getty Can’t get enough of PEOPLE‘s Royals coverage? Sign up for our free Royals newsletter to get the latest updates on Kate Middleton, Meghan Markle and more! Tuesday’s reception is one of the central showpiece events of the two-day meeting that takes place on Tuesday and Wednesday and is significant because it helps celebrate the 70th birthday of the alliance. NATO was established in 1949 with 12 founding members, and is now a collective defense agreement spanning of 29 countries. The United Kingdom is one of NATO’s 12 founding members and London was home to its first headquarters.