Robin Robin: How Gillian Anderson found her inner feline

Gillian Anderson has to agree that her role as a terrifying cat in Aardman's Christmas animation Robin Robin has undertones of another character she's played - former British prime minister Margaret Thatcher.

"Oh my gosh, you're not the first person to say that," says the actress, who won an Emmy for playing the former premier in the latest series of The Crown, when asked by BBC News if she thought there was a resemblance in tone.

"But I think you're right, there's a little bit of Mrs T in there, not deliberately, but yes - as I was getting into the dark, secretive, breathy tones I think she started to rear up."

Robin Robin is the Bristol-based studio's latest creation, directed by Dan Ojari and Mikey Please.

It's a short festive film about a young robin (played by Bronte Carmichael) with an identity crisis after being brought up in a household of mice.

The actress says she was surprised to find out on the first day of voiceover work for the character of Cat that the production was a musical - and that she was expected to sing.

"Actually, I didn't know it was a musical when I signed up for it, I hadn't quite read that bit of the email," she recounts.

"I was signing up to work with Aardman, who I've been a fan of for many years, so it wasn't until I was actually in the studio that I learned I'd be singing a song.

"I think they registered the shock on my face as the musicians came in with the guitars. I was slightly unnerved."

The menacing character of Cat ultimately delivers her threats towards Robin - her desired prey - half-speaking, half-singing.

"There's something very well observed in her menace I think," says Sarah Cox, the film's executive producer.

"I loved the way she did it. It's about power and the way a cat will toy around with a bird, who's at the bottom of the pecking order - no pun intended.

"I don't think any resemblance to Mrs Thatcher was intended. She was definitely paring the voice down, she wasn't ramping it up and trying to sound overtly evil, we wanted something quite creepy and manipulative."

Despite working in TV and film for nearly 30 years, Anderson says that just using her voice to project a character was challenging.

"I find it much more difficult than you might imagine. As an actor you get used to relying on facial expressions and movement and gesture and the tilt of the head here and there to express something.

"With animation, you're only using your voice, so it's figuring out imbuing the voice with all of the things you're not doing physically.

"Also, when a director is explaining what they want you to sound like, you try and it's not it and so you try again.

"So, there's a lot more trial and error in voice work, at least for me. I enjoy it but it's a very different experience from run-of-the mill action acting."

Robin Robin also features Richard E Grant, playing Magpie, and Adeel Akhtar as Dad Mouse, who adopts Robin as a hatchling.

Cox says she thinks these latest Aardman creations, like Shaun the Sheep and Wallace and Gromit, may have the potential for further adventures.

"With these characters, there's a lot of stories you can tell in that woodland area where town meets the countryside, from an animal perspective. I feel there's some contemporary Beatrix Potter-like characters there, and there's definitely more we can do if the audience like it," she says.

"I can't believe no one else hadn't thought to do a festive animated special with a robin before, so my reaction when I was pitched it was to say, 'Quick - let's make it before someone else does.'"

Robin Robin is available on Netflix now.