If you’ve seen Lily Allen’s new blonde hair, you’ve probably thought ‘oh my god, I can’t believe it!’The chart-topper’s new colour is more yellow than blonde, and it’s a problem that most people will face when trying to get from black to blonde.London Hairdresser of the Year Karine Jackson says that Lily could have saved herself a whole lot of hair heart-ache by staggering her change of colour.”Going blonde from a colour as dark as Lily’s is no easy task, even for the most experience colourist,” says Karine.”If your hair is already coloured, it may not be possible to get the desired result in one go so it could be better to go for an in-between colour that you like to help bridge the gap.” Redken Certified Colour Expert Jason Welch agrees: “You’ll probably need more than one trip to the salon, ideally starting off by having the black reduced out and some highlights put through it. “The first time you’d be reddy-brown/coppery with highlights – it’s really all about what undertones are there. Every colour has an undertone – even natural hair colour – which is why you can end up with an unexpected yellow, green or orange colour.”But it’s not all doom and gloom for Miss Allen; Karine is confident that Lily can look fantastic as a blonde after her next colour application. “When you’re in the spotlight like Lily it’s very brave to go from dark to light and all the elements are against her getting a perfect result the first time,” adds Karine. “Her second colouring should give a great result – she needs to get the colour more even by dyeing the ends up to match the roots and kill off the yellow before applying a toner. “When going blonde the mid-lengths and ends need to be coloured first, then once they are at the right shade you then colour the roots. “Because of body heat and the fact that hair is more natural at the roots, the colour here lifts much quicker. You’ll notice that the roots are brighter on Lily’s hair because the roots were coloured too early in the process.” Which of Lily’s looks makes you smile?