You think you’re going to be the one who beats it

Kate will have a hunch that given the right lotions and potions and training sessions she is going to get around the ageing thing because practically nothing has changed, thus far. That’s what plenty of women think. But to paraphrase Cher, it’s a doddle staying looking young and then one day it isn’t.

Legs will become a liability

Kate, do you still have the roller disco outfit that you wore to a party to put the frighteners/lusters on William when you were “on a break”? Of course you have! And you could still wear it, absolutely, but may we recommend that you get on with that ASAP. Also get your bare legs out whenever possible because there is a ticking bare-leg clock and in 10 years’ time you’ll be approaching shorts on holidays only.

Wear the heels

You’ve got plenty of time – but not more than 15 years – before your feet refuse to play ball.

Enjoy the people-pleaser shift 

Admittedly Kate’s in a unique position in that her job is to be pleasant wherever she goes, but for the rest of us we advise fully embracing the rush of “Fine, take it or leave it” that comes with turning 40. It’s like a settling of the foundations.

Watch the super HD make-up

You have to wear less now. Liz Hurley pays no attention to this rule, but worth bearing in mind.

Get into those tiaras and bling

Forty is when you stop wishing you could wear what the surfer kids are wearing and start claiming your glamorous female rights, including all the jewels.