If you keep up with the royals, you know there are specific guidelines to follow when greeting them. Kacey Musgraves was unaware of that, so when she met Prince Harry in 2015, she went with a casual high-five. However, it wasn’t received well by others.

“Apparently afterwards, the guy that works at the label was like, ‘No, no, no.’” the 31-year-old divulged to Access Hollywood on November 19 about the encounter with the royal. “He was like, ‘I can’t believe you gave him a high-five. That’s just unbelievable,’ He’s like, ‘No, there’s a way to address the royal family, and a high-five, going up top is not the way.’” Innocent mistake, right? Thankfully, Harry wasn’t offended! “He went in for it,” she continued. Based on the photos of their interaction, the duke was all for it — his big smile said it all.

Prince Harry and Kacey Musgraves Greeting Each Other
Matt Frost/ITV/Shutterstock

When the country singer opened up about the incident in 2018, she blamed her Texas roots for her choice of greeting. “Okay, so I’m from Texas. I haven’t read the manual on royal etiquette,” she told the BBC at the time. “I didn’t really go to elocution lessons or anything. He came up and he just seemed super friendly and I put my hand up and he went for it. We had a laugh.”

It turns out, Kacey was making history without even realizing it because apparently she’s the first person to ever high-five a royal in public, which shocked her. “Surely someone else out there is going for a high-five!” she added.

Kacey isn’t the only celeb who didn’t know the proper way to greet a royal. When Billy Eichner met Harry and Meghan Markle at The Lion King U.K. premiere in July, he had no idea what he was doing. Naturally, he was anxious. “What makes you nervous is in the days leading up to it, they email you a protocol of how you’re supposed to greet Prince Harry and they’re very intense about it,” he told Jimmy Kimmel during an interview a few weeks after meeting the couple. “I’m not kidding. You’re supposed to say, ‘Your Royal Highness.’ You can’t speak until your hands are in a handshake with his.”

Thankfully, the royals are pretty cool people who just go with the flow!