WHILE many actresses dabble in fashion design with the odd collaborative collection here or there, Kate Hudson has become a fully-fledged fitnesswear mogul with her hugely successful Fabletics brand - which later this year celebrates five years in business, and has just opened its first UK retail space. "We like calling it a presence, because it's not really one of our stores," the actress explains, curled up on a chintz armchair in a posh London hotel. "My best girlfriend here, Stephanie [Burrows], opened her new studio called POPfit, so it seemed fitting that I would put some of our product in there and have a presence."

Fabletics now has 1.2 million members - who have signed up to get monthly deliveries of workout gear - and 24 stores in America, in addition to the UK opening. So while Hudson, 38, was in town, we sat down with the actress and mum-of-two to talk all things fashion and fitness...

You're launching the new Fabletics retail space in London at a time that's pretty challenging for high street retailers - why now?

"For us, it's a little bit different because we're a digitally native brand. Being a predominantly online brand allows us to be able to take opportunities to test the market, and what we found was that when we strategically placed stores in places where we had a lot of activity, our customers became even more engaged. They wanted to go to the store, they wanted to touch and feel, they wanted the shopping experience. It's something that actually grows our brand, it doesn't take away from our brand. So it's worked the opposite in a climate now where retail is struggling."

This October will mark five years of Fabletics - do you have ambitions for where the brand will be in another five years from now?

"Yeah, of course, shoot for the stars, right?! It'd be great in five years to be the biggest athleisure line out there! That being said, I think our focus, as much as it is on growth - which is important for any company - it's really about perfecting our quality. Focusing on quality and fashion first is what we're really all about, and we know that's what our customer loves. So that for me is always the most important thing to focus on."

You're often described as 'actress-turned-entrepreneur' - is the business your primary passion now, or are you still on the look out for great movie roles?

"No, because I see it all as an extension of itself. One thing, though, that this has afforded me the ability to do is only work on the things creatively that I want to work on. So I don't feel forced to have to make a living through acting and do things I don't necessarily want to do. So that's a really nice feeling as a creative person. All the things I'm developing and doing are things I just love. But [acting] is my first and foremost - I mean, I'm a performer, that just never goes away."

Thinking about your personal style, what is the one item of clothing you wear the most?

"Good question! I really try to wear all my clothes - I make a conscious effort to not wear the same thing - but, jumpsuits! There's a couple of jumpsuits that when I'm in a hurry, I'll just put on. Actually, funny enough, I'm wearing Stella McCartney today, and she's my friend and everyone knows that at this point, but I love her jumpsuits. I think she makes really comfortable jumpsuits that are flattering. They aren't form-fitting, but they are flattering. I have a Saint Laurent jumpsuit that I love and another one by Ulla Johnson; it's a velvet, very girly jumpsuit - when I have to go out somewhere that's a little bit fancier, it's my go-to."

Who has most influenced your personal style?

"I really appreciate people's fashion, but I don't know if they influence mine. I think it's eras that make more sense in terms of what influences me. I definitely lean more towards the Seventies in terms of comfort. I'll always love a flared jean, I just like the way they make your legs look. I think they make your legs look nice and long, and I love a flowy dress, I love a disco dress - anything from the Seventies."

Do you have a favourite designer for red carpet events?

"Honestly, it just depends. Lately, I've been wearing a lot of Valentino. I'm just loving the gowns that come in from Valentino. But you know, the reality is that everybody does such beautiful work, and there's some people that do work that I wish I could fit into their samples! It's like, you see a dress and they come in and you're like, 'Oh I'd give anything to [wear this]', and then you put it on and you can't close it! I do love working with Versace Atelier, because for a red carpet, there's something about the way they design their dresses and the way my body is formed. I always feel so good in a Versace dress."

After shaving your head for a movie role, you've now got a blonde pixie crop - are you going to stick with it or grow it out?

"I'm not dying for it to grow out, I'm enjoying it, it's different. I'm excited for all the different stages, and now I think it's fun that if I know I want to cut my hair short again, I won't be so scared to do it, it won't be so scary. But I am going to grow it out."

A selection of Fabletics clothing is now available in store at POPfit studio (http://wearepopfit.com).