The royals have to follow certain rules - whether it's not wearing this colour nail varnish, refusing gifts from the public or closing your own car door, protocol dictates what you can and cannot do when you're a member of the royal family.
But there are also rules to be followed when you're a non-royal. If you ever find yourself at dinner with the Queen, you cannot sit down until she does, you have to wait until she starts eating before you can and you must address her as Your Majesty - but there is one person who is not a member of the royal family who broke protocol and called Queen Elizabeth II by her first name, and he was the only one permitted to do so.
Royal Commentator, Richard Fitzwilliams, revealed who historically addressed the monarch as 'Elizabeth' whenever they met.
Speaking to Express, he said: 'Mandela was. He called her Elizabeth and his affection for her was warmly reciprocated.
'Her state visit to South Africa in 1995 when he was President was one of the highlights of her reign.'
Nelson Mandela and Queen Elizabeth II's became good friends, with Mandela's former assistant writing in her book: 'On a visit to Britain, I was struck by the warm friendship between Madiba and the Queen.
'I think he was one of the very few people who called her by her first name and she seemed to be amused by it.'
Aw.
