Prince Harry Celebrated His 40th Birthday at a Charity Tennis Match Alongside Meghan Markle

Prince Harry celebrated his birthday on Sunday, September 15, with Meghan Markle at the George Zajfen Tennis Tournament in Los Angeles, Calif.

The charity gathering raises money for the Alliance for Children’s Rights, which honors Kelly McKee Zajfen 's late son, George . The sporting event is sponsored by the Sussexes' Archewell Foundation, and Zajfen was grateful for the couple's support in an Instagram post.

"But first, to our Presenting Sponsors, The Archewell Foundation. Harry and Meghan, you have been such a guiding light for our family not just in the way you have shown up in friendship but how you have shown up through the incredible work The Archewell Foundation does everyday," Zajfen wrote in an Instagram post.

"I’m in awe of your commitment to community and to friendship," she continued. "On behalf of the Alliance for Children’s Rights, we thank you. On behalf of our family, we love you. Extra special day too…HAPPY 40th Birthday H! ✨ May this trip around the sun be the best yet."

While Harry celebrated his big day in the U.S., Prince William and Kate Middleton acknowledged the duke entering a new decade of life via social media. OK! previously reported royal expert Michael Cole claimed the pair's social media activity doesn't mean they couple's feud with the Sussexes has ended.

"The big surprise of today is that the Prince and Princess of Wales added their birthday good wishes to those of Buckingham Palace," Michael Cole told GB News . "Now there's been none of that for at least two years. So what should we read into that? Well I would say it is definitely not an olive branch."

Cole later stressed that the princes are "still at war" and described the X post as doing the "right thing" during a turbulent period for the royals.

Fans of William and Kate were surprised to see them mention Harry after the Sussexes painted them as "formal."

"Wishing a Happy 40th Birthday to The Duke of Sussex," William and Kate wrote on Sunday, September 15.

"Thank you for being the adults in the room," one user replied. "As Prince Harry continues his attacks this will make him look even worse."

"Now this is extremely surprising fair play William," another penned.

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In a statement, Harry admitted he was looking forward to beginning a new chapter of life.

“I was anxious about 30, I’m excited about 40 ,” the dad-of-two told the BBC. "Whatever the age, my mission is to continue showing up and doing good in the world."

"Becoming a father of two incredibly kind and funny kids has given me a fresh perspective on life, as well as sharpening my focus in all my work,” Harry continued. “Being a dad is one of life’s greatest joys and has only made me more driven and more committed to making this world a better place.”