These meet-and-greet situations, however, can also be fraught and anxiety-ridden for those who receive an invite.

Handshake or no handshake?

Who speaks first, the celeb or the royal?

Helen Mirren with Queen Elizabeth II

And what kind of conversation topics should be broached when making small talk with royalty?

To find out more, keep reading for a rundown of embarrassing things celebrities did when meeting royals.

“It was an awkward moment,” Janney admitted, adding, “I called her ‘honey.’

Kate Middleton and Allison Janney

That might not have been royal etiquette.”

““It’s kind of a frightening thing, going to the palace,” she observed.

“Yeah, it was pretty much all I managed.”

Emilia Clarke and Prince William

“And I’m looking at her.

And you’re free to’t say anything,” explained Mendes.

“You’re not allowed to speak to her unless she speaks to you first.”

Shawn Mendes and Queen Elizabeth II

“She didn’t look at me at all.

It was super weird.”

This weird voice comes out.”

Helen Mirren meeting the Queen

They met again in 2019, when Mirren was invited to have tea with the Queen.

Mirren, however, drew a blank at how to address him or if she should ask at all.

“I mean, is it sir?

David Duchovny and Prince Charles

Is it Your Majesty?

Is it Your Highness?”

“Is it rude to ask him to pass the milk?

Margot Robbie and Prince Harry

Or should I just ask for a lackey?”

Ultimately, Mirren drank her tea sans milk.

And he said, ‘Yes, hey.'"

Ben Affleck giving side eye

Robbie recalled during an appearance on “The Tonight Show Starring Jimmy Fallon.

“"[Harry] got really offended,” Robbie joked.

“He was like, ‘Shut up!'”

The Queen meeting Lady Gaga

“He’s the most normal guy ever.

I didn’t realize it was him,” she explained.

“I just thought it was a guy named Harry and thought, ‘What a nice guy.'”

The Spice Girls with Prince Charles

“You know, germy balls they kick around,” Affleck jokingly described the place.

“And I thought, ‘Wow, Kidnasium istight,” Affleck quipped.

It then dawned on him, albeit slowly, just what he had wandered into.

Emma Thompson and Prince William

“So now I can tell him, ‘You got a cold from the King of England.'”

“Oh I love this one!”

Gaga said of what she wore to the Royal Variety Performance.

She then gave him a kiss on the cheek, leaving a bright red lipstick mark.

Probably not coincidentally, Charles was whisked away immediately after that.

“I didn’t pinch Prince Charles’s bum, as was reported.

I patted it,” she clarified in a 2016 interview withThe Times.

“I made a very loud and inappropriate noise in Buckingham Palace,” shedeclared.

Subsequently appearing on"Live with Kelly and Ryan,“Thompson was asked what she said to William.

“I was saying, ‘Darling, how are you?

I’m so proud of you, can I give you a kiss?’

because I’ve known him since he was little,” Thompson explained.

“And he said, ‘No, don’t do that, otherwise everyone will want one.'”