WATCH: Countdown to the coronation of King Charles
Kate, the Princess of Wales, met the first ladies of Ukraine and the United States at a reception ahead of the coronation of King Charles III.
Kate posed with U.S. first lady Dr. Jill Biden and Ukrainian first lady Olena Zelenska at Buckingham Palace on Friday, where Charles hosted a reception for visiting heads of state.
Around 100 heads of state and 20 royal families from around the world are expected to attend Charles' coronation Saturday at Westminster Abbey.
Kensington Palace
The Princess of Wales meets with the First Lady of the United States, Jill Biden, and the First Lady of Ukraine, Olena Zelenska, during the Reception for Heads of State at Buckingham Palace, May 5, 2023 in London.
Charles was also photographed speaking with Zelenska during the reception, which the first lady attended with Denys Shmyhal, the prime minister of Ukraine.
Jacob King/POOL/AFP via Getty Images
Britain's King Charles III speaks with Ukraine's First Lady Olena Zelenska and Ukraine's Prime Minister Denys Shmyhal during a reception for overseas guests attending his coronation, at Buckingham Palace in central London, May 5, 2023.
Biden was spotted at a different point in the reception having a second conversation with Kate alongside her granddaughter, Finnegan Biden, who accompanied the first lady to the U.K.
Jacob King/Pool via Getty Images
Catherine, Princess of Wales speaks with the first lady of the United States, Jill Biden and her grand daughter Finnegan Biden, during a reception at Buckingham Palace for overseas guests attending the coronation, May 5, 2023 in London.
Earlier in the day, Kate and Charles were joined by Prince William as they surprised fans waiting outside ahead of Saturday's festivities.
Toby Melville/Pool via Reuters
Britain's Catherine, Princess of Wales, meets well-wishers during a walkabout outside Buckingham Palace ahead of the coronation of Britain's King Charles and Camilla, Queen Consort, in London, May 5, 2023.
Toby Melville/Pool via Reuters
Britain's Prince William meets well-wishers during a walkabout outside Buckingham Palace ahead of the coronation of Britain's King Charles and Camilla, Queen Consort, in London, May 5, 2023.
Toby Melville/Pool via Reuters
Britain's King Charles reacts as he meets well-wishers during a walkabout on the Mall outside Buckingham Palace ahead of his and Camilla, Queen Consort's coronation, in London, Britain, May 5, 2023. REUTERS/Toby Melville/Pool
The trio were seen shaking hands with fans and taking pictures along the same procession route that Charles and his wife Camilla, the Queen Consort, will take from Buckingham Palace to Westminster Abbey for the coronation service.
MORE: King Charles III and Queen Camilla's blended family to be on display at coronation
Over 2,000 invited guests are expected to attend the service inside the Abbey.