A good haircut can be as jaw-defining as filler, Botox or, indeed, surgery, for it is the beauty equivalent of a bespoke tailored suit that sculpts your curves (or in this case, your facial features) into their most flattering proportions.
And at Sunday night's Emmy Awards, I was in no doubt - the asymmetric jaw-length bob is not only the haircut of the season, it is the most youthful hairstyle for women over 40.
Actresses Naomi Watts, Taraji P Henson, Michelle Williams and Fleabag's Phoebe Waller-Bridge all walked the red carpet for the 71st Emmy Awards sporting a sculptural bob.
While you might assume that such a sharp, definitive cut could be less flattering than its soft, shoulder-skimming sister (aka the lob), in fact a 1920s-style cut that is slightly longer at the front than the back is a youthful way to accentuate your jawline and elongate your neck. These are the five things that make this cut ageless...
An asymmetric cut accentuates your jawline
"When you cut the baseline of hair in at an angle by following the ear to the chin, leaving it slightly longer at the front, it accentuates your jawline and gives your facial features strength," explains celebrity hairstylist Larry King. He adds: "Having that little bit of a gap between your shoulder and your face is the length you are looking for - it's so ageless and can be adapted to suit every face shape."
A side parting sculpts your face
It is, of course, wise to be versatile with your cut and moving your parting around from the middle to the side is a great way to mix things up. But for the most impact, have your hairdresser style your new bob with a side parting - this gives you the option to tuck one side behind your ear and allow the other to skim your cheekbone, which accentuates your profile and looks youthful and modern.
Subtle waves soften your features
Whether you have naturally curly hair or merely want to add some soft waves, hair that has some texture is most flattering, especially for women over 40. Too-straight hair can be unforgiving as it puts facial features in sharp focus, and so adding a slight bend with heated tongs will soften your complexion and be more forgiving on jowls.
"You don't need to be too uniform about it, just take random sections around your face and wrap one-inch pieces of hair around the barrel of your curling tongs, leaving the ends out for a fresher, more youthful look," explains Bobby Collier at Larry King.
Subtle root lift gives a facelift effect
When you're over 40, mousse (or volumising spray) is the single most important product in your hair-styling arsenal. Apply a little to roots only before blow drying to give hair a subtle lift, which will, in turn, give the illusion of a more lifted face as it brings your eyeline upwards in a similar way that defined eyebrows do. Another volume fix, spray a little bit of dry shampoo into roots after blow drying, making sure to massage it in with your fingers. This is ideal for fine hair as it stops it from looking flat.
A striking colour upgrade will boost your complexion
Charlize Theron debuted her sharp asymmetric bob at this year's Oscars with a radical colour change, going from blonde to brunette. You don't have to be this bold, but taking your blonde a shade lighter, or your brown or red a tone richer, will bring out the best of your cut and make your eyes and complexion pop.