Prince William had a last-minute addition to his packed schedule. According to The Mirror, after King Charles was given the order to lighten his own agenda and take it easy as he continues his cancer treatment, his son, the Prince of Wales, attended an event for the Royal Air Force in his place. Earlier this week, during a meeting with the New Zealand women’s rugby team, the monarch explained that he had to cancel his planned trip Down Under and also make some changes to his current calendar.

“I’m extremely sorry I can’t come to New Zealand in late October because of doctor’s orders, but I hope there’ll be another excuse (to come) before not too long,” he said.

So, just a few days later, William stepped in for his dad—who is, thankfully, following the advice of his medical team. In the past, his wife, Queen Camilla, has expressed her frustration with the monarch’s eagerness to return to work, saying that she had to keep him in order and make him slow down.

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Today, William made a stop at RAF Cranwell in Lincolnshire and took in the Sovereign’s Parade on behalf of his dad. The location has a special place in William’s heart, as it’s where he earned his pilot wings back in 2008. At today’s ceremony, he inspected the ranks and congratulated graduates in full military dress, complete with his new facial hair.

“It is my great honor to be with you today, representing my father, His Majesty The King, to mark this significant milestone in your lives and careers,” he said. “I am delighted to see so many family and friends here—I know their love and support will have been instrumental in getting you to this point. Whilst I didn’t graduate on this exact Parade Ground, I did graduate from flying training here so I know something about the celebrations that will come later, so I promise, I’ll only take a few minutes of your time!”

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He went on to thank the service members for their efforts and recognized them for their hard work across the globe.

“I do want to take this moment though, to highlight not only the importance of your achievements to date but also that of the roles you will play in supporting the futures of your countries’ Air Forces,” he said. “I say ‘your countries’, as I know that in addition to our newest Royal Air Force officers on parade today, there are also officers from Jordan, Kenya, Pakistan, and Uganda. Multi-national relationships are key to international defense, security, and peace.”