The Duke of Sussex travelled to Aspen, Colo. to compete in the match, which is an annual event benefitting the charity he helped form in 2006 with Prince Seeiso of Lesotho. Sentebale, which means "forget me not" in Sesotho, works with children living with HIV and vulnerable communities in Lesotho and Botswana.
"This is one of several donations I plan to make to charitable organisations and I'm grateful to be able to give back in this way for the children and communities who gravely need it," Harry said in a statement.
"The Sentebale Polo Cup is critical to securing the funds needed to advance this important mission, and I'm thrilled to be able to support Sentebale, both in person and financially through a separate charitable donation to meet this immediate need.
"Our refocused mission at Sentebale is about addressing the most-immediate needs of vulnerable children in Southern Africa, helping them access vital health services, receive necessary care and build skills to be more resilient and self-sufficient in the future."
This isn't the first time Harry has made an appearance at the event. He's competed in 2019 and 2018, famously being greeted by Duchess Meghan with a huge smooch after winning the trophy the latter year. The two were newlyweds at the time. This year, the Duchess of Sussex did not attend. She gave birth to the couple's daughter, Lilibet, in June, and both she and Harry have been taking some time off.
Earlier this week, the Sussexes released a statement expressing their heartbreak and sadness at what has been happening in Afghanistan and Haiti. In a message posted on their Archewell website on Aug. 17, Harry and Meghan encouraged people to reach out and support each other.
"The world is exceptionally fragile right now," they wrote. "As we all feel the many layers of pain due to the situation in Afghanistan, we are left speechless.
"As we all watch the growing humanitarian disaster in Haiti, and the threat of it worsening after last weekend's earthquake, we are left heartbroken.
"And as we all witness the continuing global health crisis, exacerbated by new variants and constant misinformation, we are left scared."
The Duke and Duchess of Sussex championed those who have global influence to "rapidly advance the humanitarian dialogues" at events, and pointed out the United Nations General Assembly and the G20 Leaders' Summit are happening this fall. They have also provided a list of resources, including links to places to support and mental health resources.
Harry also released a statement encouraging veterans to be there for each other as the situation in Afghanistan continues to unfold. The Duke of Sussex is a veteran of the Afghanistan War, having served two tours there in 2008 and 2012, and founded the Invictus Games as a way to help support wounded and injured service members and veterans following his time there.
Harry's memoir will be published by Penguin Random House in the fall of 2022. It's described as an "honest and moving" book which will be a "definitive account of the experiences, adventures, losses and life lessons that have helped shape him" in his time as a senior royal and since he and Meghan stepped down from those roles in 2020.
"I'm writing this not as the prince I was born, but as the man I have become," he said in a statement when the book was announced in July.
"I've worn many hats over the years, both literally and figuratively, and my hope is that in telling my story – the highs and lows, the mistake, the lessons learned – I can help show that no matter where we come from, we have more in common than we think.
"I'm deeply grateful for the opportunity to share what I've learned over the course of my life so far and excited for people to read a firsthand account of my life that's accurate and wholly truthful."