According to 57-year-old Clarke, who looked after the hair of Princess Diana and the Duchess of York and has counted Cate Blanchett, Sharon Stone and Elizabeth Hurley among his many celebrity clients, the worst thing a woman can do to her hair is let it go grey.
"Until [a woman] is really old, [she] can't be seen to have any grey hairs," he told Daily Mail columnist Sebastian Shakespeare at a party at his Mayfair salon.
"Kate needs to get rid of her grey hair — it's not a good look," Clarke added.
We're struggling to spot a single grey strand in recent pics of the Duchess but it's possible Clarke is referring to Kate's public appearance earlier this year with visibly grey roots.
Um, was he the only person in the world not to know that Kate was heavily pregnant at the time? It's therefore highly likely that she had other things on her mind. For most mums-to-be, things like getting enough sleep and trying not to vomit tend to knock root-retouching off the top of the priorities list.
Of course, it's different for men, as Clarke is quick to remind us. "Men can go grey in their mid-50s and still be considered attractive — it’s the whole silver fox thing — but it's not the same for women," he said. "Kate is such a style icon that even a few strands of grey would be a disaster, so I highly recommend that she cover it up. I hate grey hair."
More: Why your hair turns grey
Yes, for women a few strands of grey hair is indeed a disaster. Aren't men lucky that they don't have such catastrophic things to deal with?
Speaking of those silver foxes, isn't it interesting that the language we use to describe men with grey hair is so dignified, so sleek, so darn tasty ("salt and pepper")? If George Clooney was to get rid of his grey streaks women across the world would be up in arms. What if Angelina Jolie stopped covering up her grey? It would be a very different story.
Because when it comes to women who aren't bothered about disguising their grey, who couldn't care less about ageing, or who are too busy doing far more important things to sit in the hair salon for a few hours every 4 to 6 weeks no such terms exist. Rather than silver foxes, these women are simply "going grey," which makes it sound as if they are gradually becoming less vibrant, less vivacious, less interesting. It's basically just another way of saying "getting old."
Women have always been encouraged to hide their grey hair because it's seen as a sign of ageing and what's more unattractive than an ageing woman? However many women first notice grey hair when they are barely out of adolescence. A friend of mine has hair so dark she has been dying her noticeably grey strands since she was a teenager and her daughter is following suit.
There's a big difference between denying the natural ageing process — because society and the media drill it into our heads from a young age that this is not something to celebrate — and covering up grey hair because it makes us feel fresh, attractive and, yes, youthful.
But to call out a young, pregnant, mum-of-two for missing a hair appointment (whether she's the future queen or the girl next door) is ridiculous.
And you'll see personalized content just for you whenever you click the My Feed .
SheKnows is making some changes!