You're hardly able to open a magazine these days without seeing Kelly Hoppen smiling out at you. She's lounging across cream sofas or perching on plastic seats hanging from ceilings, looking positively perfect with her strawberry blonde mane as eye-catching as her interior design in the background.

But underneath all this seeming perfection is a designer and business that's currently stretched to the limit. Hoppen and her team of 35 have just finished working on a boutique hotel, the Murmuri, in Barcelona, a showroom in Hong Kong for rock n' roll jeweller Stephen Webster, the MCM flagship store in London's Sloane Street, and a bespoke beauty counter for Körner Skincare at Harvey Nichols.

Her exhibition with furniture designer, Squint, for London Design Festival this month has also been a top priority, as have been the 30-odd projects still underway in places as far afield as Seoul and Florida. Oh, and having finally moved out of her £5m Battersea pad, Hoppen’s also working on renovating a new home (more of which later).

"I'm trying to have less to achieve every year because I just don't think you can get it all done."

It's little wonder then that the 'Queen of Cream', nicknamed for her trademark use of the colour, has just taken her first extended holiday in years. "We shut down for a couple of weeks and I gave all my staff extra holiday time because we were so exhausted. We've been so incredibly busy that I felt I had to,"sighs the South African-born designer, who moved to England at age two with her older brother, now an art gallery owner, her mother, an art dealer, and her father, who worked in fashion before tragically dying at age 48.

Hoppen doesn't normally do breaks. The designer has worked solidly since she was 17, setting up her own company, complete with a 'tiny studio' in Lots Road, Chelsea. Since then, she's only taken one year off - after the birth of her daughter, Natasha, in 1983.

"It is a stressful job, incredibly time consuming and you’re always, always, always relying on other people."

Now 33 years in the industry, it doesn't look like Hoppen's going to change this soon, though she insists she is doing her best to slow down. She's complained in the past about the speed expected of her industry, admitting her fastest ever project was six-weeks for friends David and Victoria Beckham in LA, a time-frame she will never repeat. She still insists of her profession now: "It is a stressful job, incredibly time consuming and you're always, always, always relying on other people."

But Hoppen also loves it, and is attempting to be more realistic herself these days. "I'm trying to have less to achieve every year because I just don't think you can get it all done. If you can choose three or four things to do that are new, then I think you're doing well."

Her three or four things are not for the faint hearted. Like her TV ambitions. "I'd like to do my own TV show, which is very different, and which we will do eventually,"she insists. In the meantime, she's taken the camera by the lens and started filming the renovation and re-design of her new home for a documentary on her website. "It's so people can follow the real tantrums and tiaras onsite, and see that it happens to all of us, even me."

There's also the book Hoppen wants to get published. It's different from the five, design-led ones she already has. "Every two years we launch a new book, but this one is totally different. It's a about when I started out in business. I'm working on it at the moment even though I don't have a publisher yet."

But the biggest new challenge is Hoppen's decision to look for outside investment in her business for the first time ever - a search that starts this month. "I really want to build the business over the next five years. It's already global in that we have an office in New York, London and Paris, but it could be an awful lot bigger. So there's definitely potential here for somebody to come in as an investor and really take the brand global."

The upside of this will mean turning down less business for capacity reasons, projects that are supposedly never less than £300,000. It's also an opportunity to enter new markets 'like property', she says. But the potential downside is Hoppen having to spread her already precious time even further.

So far, she's managed it, balancing a thriving business with an even more hectic social life. She is twice-divorced – Hoppen's second marriage was to Ed Miller for 15 years, father of actress Sienna and fashion designer Savannah – and she has never had any shortage of male admirers.

Her current beau is 49-year-old celebrity hairdresser Nicky Clarke, though she's also dated film star Jamie Foxx, TV presenter Jamie Theakston and footballer Sol Campbell, who was 15 years her junior. Not bad for a woman who turns 50 next year. "I don't feel like I'm 49,"she admits, "but then age means absolutely nothing to me."

Keeping herself in tip-top shape does matter though, which explains her sylph-like figure. "You have to work at it [to look good]. I have trained and worked out since I was 17 and I enjoy it, it's very much part of my life. I also eat very well, it's all about balance."

Well, yes, but it's about balance across areas of life, right? Suddenly I'm not so sure. With the amount of energy and determination Hoppen has, and a glance at what she's already achieved – a multi-million pound business, collections of paint, furniture, chinaware, carpet and books – it seems 'balance' isn't always the answer.

London Design Festival takes place between 13 and 23 September. For more information, or tickets, Call +44(0)20 7734 6444 or email info@londondesignfestival.com

By Barbara Walshe