Prince Harry has said he is “excited” to reach his 40th birthday ahead of the milestone on Sunday.
The Duke of Sussex said that while he had been “anxious” about turning 30, he was looking forward to the next decade.
He plans to celebrate the occasion with family at his home in California before heading off with a small group of friends on a break.
In a statement to the BBC, he said: "I was anxious about 30, I’m excited about 40.
“Whatever the age, my mission is to continue showing up and doing good in the world.”
The prince spoke of his pride at becoming a father in the last decade, saying his children Archie, 5, and Lilibet, 3, had given him a “fresh perspective” on life.
“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.
"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."
The royal, who quit The Firm in 2020 to live in the US with the Duchess of Sussex, has previously spoken about his difficulties when turning 30, a year after completing a tour of Afghanistan in 2014.
He wrote in his memoir that he had been "going through a bad moment" at the time, suffering periods of lethargy and "terrifying panic attacks.”
It comes amid speculation earlier this month that the prince could be planning a move back to the UK.
Media reports suggested he could be planning a phased return amid restlessness in California.
However, sources close to the royal have quashed those rumours, telling media outlets that he would not do so because of fears of security in the UK.
He is currently engaged in a legal battle with the Home Office over the level of police protection he receives in the UK.
In May, he made a solo visit to London for charity work, while at the end of last month he visited the UK for a memorial service to his uncle, the late Lord Robert Fellowes, brother-in-law of Princess Diana.