Britain's Prince Harry and his wife Meghan have named their baby son Archie Harrison Mountbatten-Windsor, the couple said on their Instagram account.

"This afternoon Their Royal Highnesses introduced Her Majesty The Queen to her eighth great-grandchild at Windsor Castle," the couple said. "The Duke of Edinburgh and The Duchess' mother were also present for this special occasion."

The Duke and Duchess of Sussex have presented their new-born son to the world's media at Windsor Castle.

The prince, who is seventh in line to the British royal throne, was born on Monday and the couple chose to spend time together with family before showing him to the world.