As the new series of Poldark hits our screens, Susan Griffin meets its latest star - a Cornish-born actress who had fun playing the trouble-making Tess

Great British Life: Sofia Oxenham as Tess. Copyright Mammoth ScreenSofia Oxenham as Tess. Copyright Mammoth Screen (Image: Mammoth Screen)

Sofia Oxenham was standing on the platform at Bodmin Parkway when she got the call to say she'd been cast as troublemaker Tess in Poldark.

"My agent phoned and said, 'It looks like you're going to be spending more time down there'. Obviously, it had been on my mind and I was dying to get the part, so I was over the moon. I just couldn't believe it at first, and then the nerves started to creep in," says Sofia, who was travelling back to London after visiting her family in Trebetherick.

She'd just finished filming an episode of Grantchester, her first professional job following drama school, when she auditioned for Poldark. "It was for another part and didn't hear anything for a bit and then they said, 'Can you come back in and read for Tess?' It was about a week later when I heard I got the role, and then we had a read-through with all the cast in early September. I was so nervous beforehand, being the newbie and joining an established show. It was a mixture of excitement and real fear, but everyone went out of their way to be friendly and make me feel like part of the gang straightaway."

The first day of filming was at Chavenage House in Gloucestershire, which is used as George Warleggan's house Trenwith. "I found it a bit hard to sleep the night before," admits Sofia. "It was the first day of shooting the series and they knew it was going to be the last one, so there was a lot of hype. There were horses and a carriage, and cranes, and so many people. I remember being just so petrified when I first walked on set, but Jack (Farthing, who plays George) was so nice. By the end of the day, I felt so much more comfortable."

The shoot lasted six months from September, but the series spans a year, which meant pretending it was summer in the depths of winter. "There were so many fun days because of all the incredible locations," says the 25-year-old actress.

Great British Life: Sofia Oxenham on the set of Poldark. Copyright Mike HoganSofia Oxenham on the set of Poldark. Copyright Mike Hogan (Image: Archant)

"Filming on the beaches was amazing. We had some glorious days on Holywell, near the beginning of the shoot, and in Charlestown where there were maybe 300 people watching over the harbour."

For this fifth and final series of Poldark, the show's writer Debbie Horsfield has bridged the decade-long gap between Winston Graham's seventh and eighth novels The Angry Tide and The Stranger from the Sea.

"She's got some characters, which are historical people, she's got the people from Winston Graham's books and then she's got people from her own imagination, like Tess," explains Sofia. "Tess is very layered and presents herself as numerous different characters throughout the series. She's a master manipulator, a real firecracker, and will stop at nothing to get what she wants, which was really interesting to play as there were no limits."

In episode one, she's stirring up trouble among the locals, so Demelza (Eleanor Tomlinson) offers her a job at Nampara to keep a close eye on her. "There's a glimmer of something Demelza recognises, maybe from the way she used to be, but Tess is bitter about people who she thinks have it easier than her, especially people like Demelza who once walked in Tess' shoes. I think the resentment is so strong, the more Demelza tries to help, the more Tess ends up hating her."

Sofia is unsure whether viewers will embrace Tess' rebellious ways or resent the impact she has on beloved characters. "Tess does cause a lot of trouble for the people the viewers love; she's constantly stirring the pot. There's the little frisson between her and Sam Carne. She thinks she can use Sam to her advantage, so she plays this role of being holy because she knows he won't be able to resist helping her and in return, she can control him."

Ross (Aidan Turner) is initially wary of Tess' presence, but begins to think Demelza might be having a positive impact on her. "She might, she might not," says Sofia, laughing.

Aidan might be known for his brooding portrayal of Poldark, but Sofia found him "absolutely hilarious and so fun".

"He has an unbelievable amount of energy and makes everyone laugh on set so much. He's really nice, really friendly.

"Obviously when you're acting with Aidan and Eleanor, it could be quite intimidating, but they were so lovely, and made you feel you were on an even keel from the very beginning."

It helped that all the cast and crew stayed at the same hotel in Carbis Bay during the shoot. "There were fun dinners, which was great because you could get to know everyone, and obviously between takes there was lots of time to hang out on set."

Sofia's dad is Australian, and her mum is Cornish but she grew up in Devon before the family, including her two brothers and one sister, moved to Trebetherick when she was in her late teens. "We were always at the beach, no matter what weather. My favourite is called Tregardock near Delabole, which is pretty remote and beautiful," she says.

Her eldest brother's interest in acting sparked her own and she took part in school plays before auditioning for the Royal Academy of Dramatic Art and succeeding on her third attempt.

"Living in London was quite an adjustment, but I spent the summers in Cornwall where I worked at the Camel Ski School and now, I come back as much as I can. That's what was so nice about Poldark, that I got to spend a bit of time there."

Debbie Horsfield has hinted there could be more Poldark, so perhaps Tess could return? "I guess potentially she could. That would be cool. I would be up for it 100 per cent," says Sofia. In the meantime, she's appearing in an episode of Doc Martin later this year.

"It was the same thing, I auditioned for another part and got offered this one, but I'm so excited as Port Isaac is close to where I'm from. I'm really flying the Cornish flag."

Poldark airs on Sunday nights on BBC One.