Behind nearly every famous blonde is a skilled hair colourist, who tailors their customer’s specific shade to suit them – hence why Hollywood hair always looks flawless. One of the best in the business is Nicola Clarke, who counts Kate Winslet, Cate Blanchett, Jennifer Lawrence, Margot Robbie and Kate Moss amongst her clientele. Now at the helm at John Frieda's ultra-chic Margaret Street salon in London, Clarke’s chair reigns as the capital’s hot seat for blondes.

Below, the authority shares her advice on the five things budding blondes should consider before, during and after a big colour change...

1. Your skin tone

Ultimately, “the best way to choose the right shade of blonde is simply to talk it through with a professional colourist,” Clarke says. “Bringing photos of blonde hair you like is a great starting point” – but know that you might have to go with an interpretation of that shade to suit you. Margot Robbie’s perfect blonde may not be your perfect blonde.

Finding the blonde that suits you isn’t always easy – and unfortunately there are no quick tricks to determine whether it will. It’s all dependent on your unique colourings and tastes, but Clarke says that “your eye colour and skin tone are all factors when deciding on hair colour, whether that be light or dark.” When consulting with her clients, she takes all this into consideration.

2. Your haircut

If you have a fringe or want to cut one in, this is particularly important to note when changing hair colours. “If you have a fringe and want to go blonde, I’d recommend having your hair cut beforehand so the colourist can map out where they should put the colour,” Clarke explains. “You don’t want the stylist to cut out the new highlights or colour!”

Another reason you should cut your hair before colouring is that, “Blondes with fringes need to be regularly maintained, so highlights from the root or an all-over blonde base is best.” Regardless, root re-growth will be more visible if you have a fringe, so factor that in before making a big colour change.

3. Your lifestyle and budget

Besides working with your personal colourings, Clarke says that: “Letting your colourist know a little about your lifestyle (for example, how often you can visit the salon or how you style and wear your hair) will help to determine what shade would work for you.”

Consider your budget and be aware that really big colour changes require much more upkeep than a subtle one. Changing your colour dramatically is always going to be high maintenance. "The term ‘high maintenance’ actually comes from blonde hair,” Clarke says. “You will need to be prepared to make regular visits to the salon for toners and glosses as hair that has been lightened will fade quickly as it is more porous.”

You also have to keep on top of the roots, “especially if you have bleached your hair or have lightened it all over – every four-six weeks is the commitment level needed to avoid colour bands and patchy colour,” Clarke explains.

While the expert always use treatments such as Olaplex when doing big colour changes, “to keep the internal bonds of the hair strong,” she also suggests using shampoo and conditioners recommended by your colourist at home, “given that a brunette shade might have different requirements than that of an ash blonde, for example.” Noted.

In terms of other lifestyle changes, it could also be a case of new colour, new clothes, Clarke points out below. Especially if you have gone from a warm tone to a cool one, or the other way around.

4. Your wardrobe and make-up

“Changing your hair colour does mean you might have to alter your wardrobe and a few key make-up items, but it doesn’t need to be dramatic” Clarke explains. A good colourist will try to factor this in when deciding on your shade, “for instance if you are a cool toned brunette and opt for an icy blonde then that Russian Red lipstick you wore should still suit your new blonde hair,” she notes. But if you’re going from cool to warm shades or vice versa, you will notice your previous make-up will look very different on, so you might want to experiment with changing shades.

As for your eyebrows, you won’t necessarily have to take them lighter in line with your locks, but again – it depends on your preference. “Currently the trend for brows is for them to be slightly darker and bolder than the rest of the hair. So, if you have a brown brow and blonde hair it’s cool to work this dramatic look,” Clarke feels.

“If you do lighten your eyebrows then they should always be done using an ash-toned colour, as brassy brows are a no-no,” she adds. “Also, as a rule of thumb, go no lighter than two shades of your current brow colour.”

5. Your timescale

“Give your colourist at least six months to a year if you want a big colour change,” Clarke says – confirming that dramatic changes can take time and patience.

“Going from dark to blonde should be done with care and ideally over a few visits to maintain the condition of the hair,” she explains. “We recently took a brunette actress lighter for a TV role and it took two visits of over four hours a time to achieve the correct tone.”

While often famous faces make it seem a breeze to go blonde overnight, know that there may be some trickery involved.

“With Kate Winslet, for example, or any actress who may be working on a number of films at the same time, it would be impossible to change her hair colour so repeatedly. Taking hair to colour extremes too often is far too damaging for the hair, so I will often colour wigs to fit a character.

“These wigs are made from human hair and can be coloured and fitted to look undetectable from the actor’s own hair,” Clarke reveals. Now, that takes high maintenance to another level.

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