THORNBURY (England) • From curtsying to Queen Elizabeth to calling her "Your Majesty", American actress Meghan Markle will have to learn her royal lines when she marries Prince Harry and joins the ranks of the British monarchy.
Unwritten rules govern how the royals should behave and the public act around them. While many antiquated protocols have fallen by the wayside, there is still some etiquette Markle will be expected to follow after her wedding to the Queen's grandson on May 19.
"The problem is that she's got to remember that, as a member of the royal family, she represents the family or, as it's been called, 'the brand'," said Mr Grant Harrold, who served as a butler to Harry himself while working for his father Prince Charles, and now provides expert guidance on the subject.
"So, I think there is quite a lot of pressure to make sure she gets it right because the last thing she wants to do is do something wrong or make a mistake and it ends up becoming front-page news - and then it's embarrassing for her and for the royal family," he said.
For someone who grew up in Los Angeles, life behind palace walls - where butlers, footmen and members of the royal household, often dressed in smart traditional uniforms with scarlet waistcoats, discreetly go about their jobs - could scarcely be more different.
"I think Meghan will cope - but she will find some of the flummery difficult to bear," said Andrew Morton, who has penned a biography of the bride-to-be. "This was a girl who was a gender equality advocate for the United Nations - having to bow and curtsy to the queen and even (her future sister-in-law) Kate Middleton in private occasions."
Mr Harrold says the formal protocol surrounding the royals, such as when to bow or curtsy and to whom, and how to eat at royal banquets, was mostly set by 17th-century French king Louis XIV before being embraced by other sovereigns.
But as the monarchy modernises, these conventions are not as important as they once were, something the royals themselves acknowledge.
"There are no obligatory codes of behaviour when meeting the Queen or a member of the royal family, but many people wish to observe the traditional forms," the royal family's website says - before explaining how to bow and curtsy and address the Windsors.
Those who breach the unspoken rules can sometimes expect a frosty reception. Former Australian prime minister Paul Keating was dubbed the "Lizard of Oz" by the British press after he appeared to put his arm around the monarch's shoulders in 1992.
One convention Markle will particularly have to be aware of is that the British royals are expected to steer clear of making any overtly political statements in public.
"She's got to be more careful about how she's photographed and what she's doing," said Claudia Joseph, author of How To Dress Like A Princess. "She's not going to be able to be as political as she was beforehand - and that might be trouble in the future."