Signature blonde celebs such as Cameron Diaz, Scarlett Johansson and Britanny Nurphy have all experimented with their tresses in favour of the dark side of chocolate. If you are thinking of going from blonde to brunette, read our guide before you take the plunge. Whilst choosing to go a dark shade can be bold and brave, you need to ensure that the colour you choose suits you. If you want an all over hair colour change get the advice of your hairdresser – even if you want to do it yourself. Consider semi- permanent colours which wash out, so are less risky. If you're fair, ask for a semi-permanent or vegetable dye, which will fade naturally after about six weeks. Go no more than two shades darker first-time round and keep any changes subtle. If you’re not sure what colour to go for or just want to give your hair a shiny look opt for a wash in temporary colour. This washes out after a few times and doesn’t damage or change your hair colour. Medium and olive skins look best with cool, ashy brown, while Black skin suits dark shades warmed with light-brown highlights. Colour-treated hair must be looked-after and investing in an intensive conditioner is a worthwhile idea. Wash with a gentle shampoo and always use a conditioner as well as an intensive conditioner every few weeks. Try to only shampoo twice a week as the colour could fade. If you go swimming it’s wise to wear a swimming cap.