Prince William, second in line to the British throne, is celebrating his 37th birthday in private on Friday.
“Thank you, everyone, for your lovely wishes on the Duke of Cambridge’s birthday’’ Kensington Palace tweeted, using William’s official title.
William is second in line to succeed his grandmother Queen Elizabeth II, 93, and his father Prince Charles, 70, is first in line.
Charles posted on his Clarence House Twitter account, black-and-white photograph of him playing with William in a garden at Kensington Palace in 1984.
Buckingham Palace also wished William a happy birthday on Twitter, posting several photographs of him with the queen.
William is the eldest son of Charles and the late Diana, Princess of Wales.
He and his wife Kate, the Duchess of Cambridge, have three children: Prince George, 5; Princess Charlotte, 4; and 1-year-old Prince Louis.
William served in the British armed forces for 7-and-a-half years in his 20s, training as a helicopter pilot.
In recent years, he has raised his profile as a supporter of mental health, homelessness, conservation and other charities.
He and his brother Prince Harry, 34, set up a Royal Foundation in 2009 to support their charitable work.
Kensington Palace announced on Thursday that Harry and his wife Meghan, the Duchess of Sussex, plan to launch their own separate charitable foundation.