Fans of Charles, who turned 73 yesterday, left hundreds of comments on the Prince’s post on Instagram. The post, uploaded on the Clarence House Instagram account, received over 83,000 likes and 2,600 replies.

       The Duke of Cornwall spent the morning of his birthday at the Cenotaph to commemorate fallen soldiers at this year’s Remembrance Sunday.

       Charles, who is the longest-serving Prince of Wales and heir apparent, even stood in for Queen Elizabeth II after the 95-year-old pulled out of the event with “deep regret” after suffering from a “sprained back”.

       But the Clarence House Instagram post, which was uploaded around 13-hours-ago, read: “Thank you for the kind birthday wishes for the Prince of Wales today.”

       However, warm wishes to the Duke of Rothesay only increased after the post was uploaded.

       JUST IN: 'Trustworthy' Kate Middleton favours specific colour when stepping out with family

       “Happy Birthday Prince Charles - Hope you have a lovely day for a beautiful gentleman,” Emily Daisy said.

       Another user, called Leslie, said: “Birthday wishes from the US to Your Royal Highness!”

       Sue Sturrock added: “Many happy returns your Royal Highness.

       “I’ll raise a glass to you this evening.”

       READ MORE: Former Japanese Princess Mako lands in New York to start new life with 'commoner' husband

       Other birthday wishes came from users based in Indonesia, Germany, France and even Venezuela.

       Clarence House’s Twitter post received similar responses.

       Ex-Tory MP Louise Mensch wrote: “Happy birthday Your Royal Highness! Hope you have a wonderful day.”

       “Happy Birthday Prince Charles from across the pond in Canada,” Gerard Deveau added.

       DON'T MISS:

       Queen's health concerns set to spark Christmas return for Harry [INSIGHT]

       What happens when Prince Charles becomes King - 4 key changes [REVEALED]

       'I saw her last week' Boris slaps down fears over Queen's health [LIVE]

       In response to a post uploaded on the Royal Family’s Twitter account, a user based in Wales replied: “Penblwydd Hapus i chi, HRH Prince Charles.”

       In English this translates to: “Happy Birthday to you, HRH Prince Charles.”