When it comes to meeting a member of the royal family, there are a ton of rules and regulations that must be followed.
This applies to everyone from poor farmers to celebrities and world leaders.
But despite the many celebrities who have met with members of the royal family, many have made some very royal gaffes during their meetings.
The rules cover everything from how to greet members of the royal family to how to address them and how to behave around them.
There are various reasons for this, some of which are tradition-based, others may have to do with safety.
But some have flouted the rules while meeting members of the royal family.
Not only that, but they were acquitted! So who are they?
Roger Federer
Roger Federer meets with Kate Middleton. (Karwai Tang/WireImage)
The tennis legend skipped the more traditional greeting when he met Kate Middleton in the royal box at Wimbledon.
Instead, he placed his hand on her back in greeting, ignoring the “no touching” rule that states you should never touch someone unless they have first requested it, such as by extending his hand for a handshake.
Still, Federer is known to be close with Kate's sister, Pippa, and has a closer relationship with her than most.
Joe Biden
It may be against the rules, but sunglasses really do help. (Samir Hussain – Pool/WireImage)
The sitting US president wore sunglasses when he met the late Queen Elizabeth II during an official visit.
According to one royal butler, this is against the rules as eye contact is important during formal introductions.
But I'll leave it to you to decide how much an American leader should care about British royal traditions.
Didn't a war start about that a few years ago, in 1775 or something?
Donald Trump
Trump walked just ahead of the Queen. (Matt Dunham – WPA Pool/Getty Images)
It's perhaps not surprising that a socialite like Donald Trump would break the rules when meeting the late Queen Elizabeth.
In his case, it was because he tried to shake hands instead of bowing, and walked in front of the Queen when traditionally she should walk first.
Allison Janney
Allison Janney recalled calling Kate Middleton “honey.” (Steve Granitz/FilmMagic)
The actress recalled the time she ran up to Kate Middleton barefoot and greeted her by calling her “honey.”
A conversation with James Cordon The Late Late ShowShe said: “I called her 'honey', which may not have been royal courtesy.”
Ed Sheeran
Ed Sheeran recalls meeting King. (Winslow Townson/Getty Images)
There's no excuse for British musician Ed Sheeran not knowing about the custom when he touched the arm of the future Prince Charles.
Luckily, it didn't seem to have had any negative repercussions, as Sheeran recalls: “He asked me if I was still selling a lot of records, and I told him I had a concert in New York tomorrow, and he was so surprised I was on a plane after the concert.”
LeBron James
LeBron James meets with Kate Middleton and Prince William (Neilson Barnard/Getty Images)
The basketball legend broke the “no contact” rule when he met Prince William and Kate Middleton by putting his arm around them.
Nonetheless, insiders say the royals like convention to be broken every now and again, as it keeps things a bit more mixed up.
Michelle Obama
Michelle Obama has met the Queen multiple times. (John Stilwell/AFP via Getty Images)
In a similar incident, then US First Lady Michelle Obama placed her hand on the Queen's back during a visit.
Recalling the encounter, she said, “I did what I always instinctively do when I feel a connection with someone new, and that's to outwardly express my feelings. I placed an affectionate hand on her shoulder.”
It wasn't until later that I realised this might have been a bit rude, but the Queen didn't seem to mind.
The former first lady said, “I'm sure the Queen was OK with it, because when I touched her, she came closer and placed her gloved hand lightly on my lower back.”
