Rules Meghan Markle and Prince Harry’s wedding guests must obey when meeting the Queen

Touching Queen Elizabeth has long been considered one of the greatest taboos surrounding the Royal Family, Lucy Hume, associate director at professional ettitquete coaching company Debrett’s, said.

Other rules attendees at the May 19 bash must obey are to curtsy to the Queen and make sure they call her ‘Your Majesty’ and not ‘Your Royal Highness’, a mistake often made when nerves get the better of those in her presence.

And speaking of mistakes, one of the most common misconceptions is whether getting something wrong is the equivalent to breaking the law.

Ms Hume affirmed: “There are no official legal rules in place.

“Apologise if you feel you may have caused offence, but try not to panic, and stay calm.”

She added: “It would seem from what we’ve seen of members of the royal family in public that they are very accustomed to a variety of different situations.

“They meet people from different backgrounds all the time and they’re very accustomed to putting people at ease; it’s unlikely you would cause offence.”

Ms Hume does warn that should the lovebird’s guests want to try their luck at a selfie with the Queen, it is definitely but to ask first so as to respect boundaries.

She said: “It’s not usually appropriate to do so.

“So if you do want to take a photograph, ask their permission first, possibly get somebody else to take a photograph but it’s important to respect that person’s personal space.”

Ms Hume concluded that women must curtsy and men are expected to bow in her presence.

The wedding – dubbed the biggest of the year – will take place on Saturday May 19 at St George’s Chapel in Windsor, Berkshire with millions either flocking to the quaint town for a sneak peak of Ms Markle in her rumoured £100,000 Ralph & Russo grown or watching it on the telly.

The royal protocol comes as it was confirmed Meghan’s father Thomas Markle will be walking his former actress daughter down the aisle.

Meghans mother, Doria Ragland, will also be in attendance, and both will be arriving in the UK ready for their daughter’s big day next Monday.