Prince Harry received support from two of Princess Diana’s siblings at his engagement in the U.K. today.

The Duke of Sussex attended the Invictus Games Foundation’s 10th Anniversary celebration at St Paul’s Cathedral on Wednesday. The event marked 10 years since the inception of the games, which are a Paralympic-style event for wounded service people and veterans.

The service was attended by two siblings of the late Princess of Wales: Charles Spencer and Lady Jane Fellowes.

The duke was also joined by actor Damian Lewis, who read the poem “Invictus.” Harry once named Lewis as the actor he’d want to portray him in the Netflix series “The Crown.”

King Charles and Prince William both had other engagements on Harry’s big day.

The monarch and Queen Camilla held a garden party at Buckingham Palace, which was attended by members of the royal family including Princess Anne, Prince Edward and Sophie, the Duchess of Edinburgh.

The Prince of Wales was also previously engaged, as he conducted an investiture ceremony at Windsor Castle earlier in the day.

A spokesperson for the Duke of Sussex confirmed to HuffPost on Tuesday that the prince would not be able to meet with Charles while he was in the U.K.

“In response to the many inquiries and continued speculation on whether or not The Duke will meet with his father while in the UK this week, it unfortunately will not be possible due to His Majesty’s full programme,” a spokesperson for Harry said in a statement shared with HuffPost.

The spokesperson added that “The Duke of course is understanding of his father’s diary of commitments and various other priorities and hopes to see him soon.”

While Meghan Markle did not accompany Harry for his brief trip to the U.K., she will join him later this month for a trip to Nigeria.