From pleather pants to high-end designer wear: Inside Costeen Hatzi's incredible transformation as Nick Kyrgios' girlfriend reveals celebrity style icon

Nick Kyrgios' girlfriend Costeen Hatzi has undergone quite the style transformation over the years since kicking off her career as a fashion influencer.

The Australian tennis WAG, 24, rose to fame three years ago when she began dating tennis pro Nick, 29, and has now become a hugely popular social media star.

She has worked with a whole array of top brands and even walked in her very first runway show at the Hunting Hue launch in Sydney last month in a major milestone.

Now well-known for her flawless style, Costeen also rakes in between four and five figures for each of her sponsored posts as she makes a living off her wardrobe.

However, it has been quite the journey for Costeen as she admitted she hasn't always had the same eye for fashion while speaking exclusively to Daily Mail Australia.

Around three years ago, she instead could be seen sporting cropped shirts, pleather trousers and neon tones, rather than the elegant evening wear she is now known for.

'Maybe like three years ago when I started seeing Nick, I didn't know what styles worked for me and I got photographed in like, not the best clothes,' she admitted.

The Sydney-based businesswoman said celebrity fashionistas including Hailey Bieber have heavily influenced her fashion evolution, as well as her regular use of Pinterest.

She shared: 'Hailey Bieber, I love what she wears, she's such a style icon. I feel like every young girl would say Hailey Bieber. 

'I really love what Nadia Bartel wears [too], she's got the brand Henne and I love what she wears, I love her.'

Discussing how her style has changed, Costeen said she now opts for 'classier' and more glamorous ensembles, and will slip on a pair of heels rather than white trainers.

Throughout her fashion journey, the Style Studio Dress Hire owner said she has come to learn what looks good on her body shape and what colours suit her.

'Sometimes I look back to outfits that I was wearing maybe three or four years ago and I just feel like my style has evolved and changed so much,' she said.

'I feel like I'm leaning towards more of like the clean, luxurious kind of look now. I like wearing classy outfits, I'm wearing a lot more heels now.' 

 'It's definitely evolved a lot and I feel like I have an eye for it now, I know what goes with what. 

'I wear pretty basic colours, I'm not one to wear bright colours in day-to-day life, but I feel like I've learnt so much in terms of fashion, what goes with what and what fits my body shape, and what works for me. 

'Working with all these brands as well over the past few years has also really moulded my fashion taste.'

Though her style has massively changed since she started dating Australian tennis star Nick, she insisted she is not necessarily taking style tips from her boyfriend. 

'Nick has actually got a very good eye for fashion but I feel like he is one to just mix and match, like he just wears anything really,' she admitted.

'The colours don't even have to suit him. I don't even say ''hey that doesn't go with that'' I just let him do his thing. 

'I think that's how most boys are, they just put on whatever fits and whatever they think looks good and they just wear it. 

'But I'm definitely more into trends than he is, he's got his own personal style - just like hoodies and Jordans, you'll never catch him not wearing that!

'I like to explore more and try things that are trending and be more open with my fashion, but he's got his style set.'

Costeen also reflected on her massive career milestone in walking her very first fashion show for Hunting Hue in Sydney last month.

Strutting the runway at Bondi Icebergs, Costeen showed off her incredible figure in a strapless one-piece swimsuit with Bronte Baths printed across it.

She put on a very leggy display in a pair of white heeled cowboy boots and added a gold Cartier Love Bracelet worth $12,000 to complete her look.

Speaking about the show, Costeen admitted she was racked with nerves before stepping on to the catwalk, but said she is still thrilled to have had the opportunity. 

'I was so nervous in the days leading up to it, but when I was there it was such a good vibe and we were all having fun,' she said.

'The highlight, I would say, I think would just be walking it and just getting out there and out of my comfort zone. 

'Look, it was nerve-racking but I wouldn't say it was bad nerves, it was more excitement. 

'I'm really happy that I did it because I was kind of overthinking it a little bit, as it was my first time walking, so I was obviously very nervous.'

Nick wasn't able to attend her show because he was driving back to Canberra, where he trains, after a Melbourne meet-and-greet with a young man called Harrison, who is fighting a chronic disease.

But Costeen was able to show her boyfriend a video of the show and said he was very 'proud' of her as she shared her hopes that he will be at her next runway.

'[Nick] loved it, he actually had to drive back to Canberra as that's where his whole training set-up is based, so unfortunately, he had to miss it, but that's OK,' she said.

'He saw a video after and he was really happy for me and proud of me. I wish he could have been there, but hopefully next time.'

Looking ahead to the future, Costeen would love to strut the catwalk again but confessed she never saw herself as a model because she didn't think she had the right body type.

'I would love to [be a runway model], but I've always thought that I'm too short or not skinny enough,' she shared. 

'Brands are more inclusive now so they're open to casting all different shapes and sizes as well, so I'm glad that they've done that.' 

'I don't see myself as a runway model or a model, but I really enjoyed it and I would definitely do it again,' she added.

Costeen didn't start her career in fashion but was studying and working at a car dealership before meeting Nick, when she launched her career as a full-time influencer.

She graduated from the Australian Catholic University with a Bachelor of Psychology in May 2021, and now runs her business Style Studio Dress Hire as well as supporting Nick's tennis career.

Costeen has been dating Nick since 2021, when they met via Instagram, and the couple are now gearing up to celebrate their third anniversary in December.

Their high-profile relationship came nearly a year after Nick split from his long-time girlfriend Chiara Passari in February 2021.