Prince Harry to celebrate 40th birthday with friends and family

Prince Harry is celebrating a milestone birthday, one he says he is "excited" to celebrate.

On Sept. 15, Harry, the youngest child of King Charles III and the late Princess Diana, turns 40.

"I was anxious about 30, I’m excited about 40," Harry, the Duke of Sussex, said in a statement to the BBC. "Whatever the age, my mission is to continue showing up and doing good in the world."

Part of his contentment appears to come from his home life with his wife Meghan, the Duchess of Sussex, and their two children, Prince Archie, 5, and Princess Lilibet, 3.

"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 told the BBC. "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."

ABC News understands that Harry will spend his 40th birthday in Montecito, where he and Meghan moved their family after stepping down from their royal roles, celebrating with his family and friends.

While visiting Nigeria in May, Meghan told students at a local school that Lili loves "singing and dancing" class because she loves to jump around, according to People.

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Earlier this year, Harry told ABC News' Will Reeve that both Lili and Archie are doing "great" and "growing up very, very fast."

"They both have got an incredible sense of humor and make us laugh and keep us grounded every single day, like most kids do," he told Reeve. "I’m just very grateful to be a dad."

Harry's milestone 40th birthday comes as he continues to have a distant relationship with his father and his brother, Prince William.

Harry's last known in-person visit with Charles was in February, when Harry traveled to the U.K. to see his dad after learning of his cancer diagnosis.

Harry also returned to the U.K. in August to attend a memorial service for his maternal uncle, Lord Robert Fellowes, according to the BBC. William also attended the service, but the brothers reportedly did not interact.