The Princess Royal, who is known for her strong work ethic, offered the advice in a 1981 documentary named ‘Princess Anne: Her Working Life’.

Princess Anne explained what it takes to be a good “companion” (Image: Finnbarr Webster/Getty Images)

Princess Anne has revealed the one crucial rule that all royals must follow when participating in official engagements, which requires being “nice and bright and cheerful”.

The Princess Royal offered the advice in a 1981 documentary named ‘Princess Anne: Her Working Life’, with a series of excerpts uploaded to YouTube under the title ‘Princess Anne at 30, talking royal life’.

In the clip, Anne is speaking about engagement etiquette to somebody just off-camera. She opened up about what it takes to be a royal “companion”, and it would appear there’s no room for “glum” people.

Anne said: “On official engagements, what you require is a companion. It’s no good to me if then, you know, you get somebody turning up in the morning looking like death and furious…

“And you know, ratty about life and non-communicative and when they go out on a trip, they’re standing in a corner looking glum and bored. I mean that’s no help at all to anyone, least of all to the people at the other end, never mind to me.”

The Princess Royal said it’s “not an easy job” (Image: Dave Benett/Getty Images for Gentleman’s Journal)

She continued: “So it is important that they should be, you know, capable of being interested and good at chatting up people, which I think they all are, and they seem to enjoy it.”

She went on to say: “It’s not an easy job because it’s like everything else. It doesn’t have a particular… You know, you can’t really describe it when you… you know, if you wanted to try and tell somebody what it involved.”

Anne said it doesn’t “come that easily”, but the role involves being “nice and bright and cheerful” even if you may not necessarily “feel like it”.

Anne, who is King Charles’s younger sister, turned 74 this week and has an “unbelievable” work ethic, US royal commentator Kinsey Schofield told GB News in May.

It follows a report that a journalist from the Telegraph was left exhausted after following the royal around for a week, despite being half her age.

In 2023, Anne landed the title of the hardest working royal (Image: Francois Nel/Getty Images)

In 2023, Anne landed the title of the hardest working royal, having carried out 457 engagements that year, according to analysis from the Sunday Telegraph.

However, Charles was a close second with 425 royal engagements and Prince Edward came third with 297, followed by Queen Camilla with 233.

In fact, Anne is so dedicated to her role, she has taken on a third of all royal engagements in 2024 so far.