Dark hair like Carol's that has been lightened so dramatically is the 'most prone to brassiness so it is so important to maintain your colour with the proper products after your salon visit.' he recommends.
Be inspired for your next salon visit with our favourite A-list celebrity bob hairstyles
Take a look at our round-up of Helen Mirren's hairstyles. Her style might have changed over the years but she always looks fabulous!
Protect your highlights and fight frizz with our top 10 sulphate-free shampoos.
Achieve straight, silky hair with our pick of the best hair straighteners