Aesthetically-pleasing TV shows are very much in vogue; Game of Thrones, Russian Doll, Riverdale, Twin Peaks, and Maniac are just some of the names that come to mind.

Beautifully lit scenes are filled with intricate costumes and Instagram-worthy backdrops; their creators' eye to detail immersing the viewer into an other-worldly story.

Last year, Phoebe Waller-Bridge's cat and mouse creation Killing Eve joined the trend, seducing viewers into a world where the stakes are as high as the fashion.

The series follows a security operative called Eve (Sandra Oh) and psychotic assassin Villanelle (Jodie Comer) as they push and pull their way to one another across some of Europe's most striking locations. 

Both women are utterly beguiling but it is Villanelle - an assassin with a penchant for Haute Couture - who plays the part of fashionable femme fatale. Her wardrobe is a thing of beauty. Spending like the maniac she is, she amasses Valentino, Burberry, and Dries Van Noten in one fell swoop.

With the help of costume designer Charlotte Mitchell, Villanelle is always dressed to kill... literally.

"Villanelle is a costume designer’s dream," Mitchell told BBC America. "She loves luxury and labels but also has a sense of her own style. She puts pieces together in her own way because she loves having fun and being playful. She's not your typical comic book assassin and likes to be outlandish.

"She knows she's good at her job and literally gets away with murder," she continued. "She doesn’t mind standing out because she is able to disappear easily. That arrogance is fantastic and it’s what I stick with when I’m designing Villanelle. She wants to show off and that’s why the colours are bright.

"She’s not a typical villain who looks dark, sinister and hidden. She is so arrogant that she doesn’t care if people notice her. She adapts her clothes to each environment and is always making a statement. There’s usually a tongue in cheek element to what she chooses to wear but she’s always hugely stylish and has such flare."

Of course, the job of an assassin has many pitfalls, one being that her outfits are often more survivalist than stylish. In season two, Villanelle's life goes off-kilter; one minute she's fleeing her hospital bed wearing a teenage boy's pajamas and nurse's crocs, the next she's trapped in a suburban home looking drab in an old woman's nightgown.

"At the start of season two, Villanelle is out of control," explains Mitchell. "There’s a ridiculousness to it which is the genius of the writing. As a costume designer, the challenge was to figure out how she would wear those clothes, feeling wretched and completely out of character. It was great fun to play with. 

"There’s a genius shot in the opening episode where Villanelle and a young boy are sat on a hospital bed together in ridiculous comic strip logoed pyjamas. Hers are made of a stretched lycra fabric which makes them look too small. It’s fantastic seeing them there together as it’s so funny. Those are the moments I enjoyed the most.

"On one hand, you’ve got the gorgeous designer side to style and on the other, it’s the comedic. But I had to be careful not to play up the comedic side and become too clichéd. Having said that, Villanelle is not a clichéd assassin, but when she chooses to play the assassin role she might wear leather and play up to it."

When it comes to Sandra Oh's character, on the other hand, clothes are all about practicality. Eve is a married professional who prioritises efficiency over aesthetics - until she meets Villanelle that is.

In season one, the killer lures her pursuer to the dark side with designer dresses, and in season two she gifts blood-red lipstick. For Villanelle, everything is a volatile game of seduction - she dangles a life of excitement, lust, high fashion, and death in front of a woman who is, ultimately, bored. 

When it comes to her wardrobe, however, no matter how confused her life may become, Eve sticks to her uniform.

"She’s not about clothes and fashion but is always about the job," says Mitchell. "In this season, she gets introduced to her new team and she does make an effort at first. She looks through her wardrobe and considers what to wear.

"Villanelle has got into her psyche but it doesn’t take over. She dresses up to a certain degree but nothing fits perfectly and it’s all a bit cheap, all very high street.

"Eve has suits that are lacklustre. They look slightly greasy, they’re worn and well used. I’ve put a lot more linen in this year which looks crumpled. It gives that feel that she hasn’t got time to iron," she continued.

"Eve would throw it on, throw it on the ground, then put it back on all creased. The lighting really picks up all those wrinkles. It’s about texture with her. Nothing is flat, they’ve all got a little bit more life to them. She has one bag and even if she went out for an evening she would pick up the same bag. She might have a couple of coats but they’re all for practical reasons; one’s a raincoat, one’s a warm coat etc.

"I’m sure many people can relate to her; rushing around, not having time to do stuff, thinking about their job, thinking about life, having problems etc. It means her clothes can’t be static and the audience shouldn’t even really notice them. Her clothes are just part of her, they belong to her. She doesn’t own them or claim them like Villanelle does, she just lives in herself."

Catch up on RTÉ Player now! Click through our gallery above to see some of Villanelle's latest looks.