Prince William and Kate shared a photo of themselves laughing during a running race with the Prince, and the caption read: "Wishing a very happy birthday to Prince Harry today!" accompanied by birthday cake and balloon emojis.
WATCH: Prince Harry celebrates 36th birthday in California
The Cambridges weren't the only royals to send birthday wishes to Harry. The Queen and the Duke of Edinburgh wrote on the royal family's account: "Wishing The Duke of Sussex a very happy birthday!" while sharing a photo of Harry with his grandmother at a Queen’s Young Leaders reception at Buckingham Palace in 2017. The Prince of Wales and the Duchess of Cornwall also shared two photos of Harry to celebrate the occasion.
Kensington Palace shared a brilliant snap of the trio
William and Kate shared a lovely photo of Meghan beaming at a young girl on a previous royal engagement for her 39th birthday in August. The couple wrote alongside the image: "Wishing a very happy birthday to The Duchess of Sussex today."
The Cambridges and the Sussexes were last reunited in public together at the Commonwealth Day service at Westminster Abbey in London in March. It was Harry and Meghan's final engagement as they stepped back from royal duties.
Clarence House's Instagram shared a photo of Harry with his dad, Prince Charles
The Duke and Duchess of Sussex moved to the US shortly afterwards, residing in a temporary home in Los Angeles before moving into their new family home in Montecito in Santa Barbara in July with their 16-month-old son Archie.
William was Harry's best man on his wedding day in 2018
Prince William is two years older than brother Harry, who was born on 15 September 1984. Growing up, the royal brothers shared an incredibly close bond, both attending Eton College and serving in the military.
Just like Harry was his best man, William returned the favour when his brother married former actress Meghan in Windsor in May 2018. The Duke and Duchess of Cambridge's eldest children, Prince George and Princess Charlotte, both had starring roles as pageboy and bridesmaid at the royal wedding.
Make sure you never miss a ROYAL story! Sign up to our newsletter to get all of our celebrity, royal and lifestyle news delivered directly to your inbox.