The King and Queen were amongst a number of royals who saw Peter Phillips marry NHS nurse Harriet Sperling on Saturday.
Mr Phillips, 48, the Princess Royal’s son, and Ms Sperling tied the knot at All Saints Church in Kemble, Gloucestershire, in a private ceremony.
King Charles III and Queen Camilla were greeted by cheers from well-wishers as they arrived, and they were joined by the Prince and Princess of Wales, and the groom’s sister and brother-in-law Zara and Mike Tindall with their daughters Mia and Lena.
Also in the congregation were the Duke and Duchess of Edinburgh with their son James, Earl of Wessex, and the groom’s cousins Princesses Eugenie and Beatrice, accompanied by their husbands Jack Brooksbank and Edoardo Mapelli Mozzi.
The Duke and Duchess of Sussex were not in attendance, and it is not known whether an invitation was extended to them and their children, despite Harry and Mr Phillips being close when they were younger.
Members of the public cheered as Charles and Camilla and William and Kate arrived, and there were shouts of "hip hip hooray" as bride Sperling arrived along with her three bridesmaids, Phillips' children Savannah, 15, and Isla, 14, as well as Sperling's teenage daughter Georgina.
Ms Sperling, who will now be known as Mrs Phillips, wore a dress designed by Emilia Wickstead, earrings by Pragnell and the Pragnell family tiara, with shoes by Jimmy Choo.
She was walked down the aisle by her brother Nicholas Sanders, in honour of their late father Rupert Sanders.
Mr Phillips had his longtime childhood friend Andrew Tucker, from Gloucestershire, as his right-hand man, a spokesman for the couple confirmed.
Following the ceremony, guests held umbrellas in heavy rain to throw cream rose petals over the bride and groom as they left the church, as family and close friends headed to Gatcombe Park, the home of the Princess Royal and her husband Vice Admiral Sir Timothy Laurence, for the reception.
However, Charles and Camilla travelled straight from the ceremony to the Epsom Derby, where they were due to present the trophy to the winner.
Mr Phillips, the son of Anne and her first husband Captain Mark Phillips, is the King’s nephew, William and Harry’s first cousin, and the brother of Zara, and is 19th in the line of succession to the British throne.
He split from his first wife Autumn in 2020 after 12 years of marriage and shares custody of their two children.
Phillips and Sperling began dating in 2024, and the pair's engagement was announced in August 2025.