Erin Doherty used to order coffees in Anne, Princess Royal's regal voice to see how people reacted.

The 33-year-old actress - who played a teenage version of the 75-year-old royal in seasons three and four of Netflix's The Crown - relishes finding out how her different alter egos fit into different social situations.

Erin told The Observer Magazine: "I remember ordering coffees in a Princess Anne voice because I was like, 'I'm just going to see if this whole interaction changes.' And it was massively different, which was interesting.

"Without being stereotypical, it got to me way quicker. My coffee was in my hand."

Asked why Erin thought she was made a priority at the coffee shop, the star responded: "There's an authority to voices like that. And whether we like it or not, you respond differently."

Erin was 27 when she landed the role of a forthright Princess Anne in seasons three and four of the streaming giant's regal drama in 2019, covering her life from the late 1960s through to the 1970s.

Erin was lauded for her portrayal of the royal - even bagging a SAG award nomination - but people are surprised that the actress is not posh in real life.

Erin said: "I remember when I did The Crown, a lot of people just thought I was posh. You could see it in their faces.

"Not in a mean way, but you're like, 'You're just hearing my voice right now, and having a bit of an out-of-body experience.'"

Erin took a break after season four of The Crown was released in 2020 so that people could "forget" her.

In February, the star - who was inundated with work offers afterward, and was still sent many scripts in which she would play another royal - told Harper's Bazaar magazine: "There was a year, following The Crown, when I got sent all the [scripts with] princesses under the sun.

"It was lovely, but sometimes you need to step away to make audiences forget you. Then you come back and take them by surprise."

Amid her success, Erin still gets starstruck.

She admitted: "I get so overwhelmed by little moments. On The Crown, I spent two whole years just trying to be a normal person because inside I was squealing.

"Honestly, I spend most of my days going, 'Erin, get your head down. Do your job.'"