You know a cutting-edge style's tipped over into the mainstream when you see the cool kids at the local high school wearing it. Not one, not two, but three of them the other morning had their long hair tied up on top of their head.
Film stars and sportsmen maybe, surfers, barristas and other fashion-forward folk too, but school kids? The man bun - longish hair tied up on top in a loose knot - has hit the big time.
But it's not that new a thing, says American Crew stylist Phoenix Thomson. "David Beckham, for example, had one a while ago. Chris ['Thor'] Hemsworth is rarely seen without one. But it's become very cool , especially now with more guys wanting to grow their hair longer." Other Hollywood stars who have been spotted with their hair up include Jared Leto, Shia LeBeouf and Colin Farrell.
"It's an easy, quick fix when you don't have much time to style your hair," says Thomson. But don't such men look a little - how can I put this delicately – silly?
"It is definitely a 50:50 thing. People either love it or hate it," says Jo Smith of Toni and Guy Georges in Melbourne's CBD.
"But as with all hairstyles it's down to suitability - whether or not it looks cool, lazy or dated. The cleaner and tighter it is, the better it looks."
And the best thing about it, Smith says, is that it gives "the illusion of having short hair when in fact you have long hair". Which could come in handy, maybe, for a job interview with someone who's not that observant.
So, assuming you want one, how do you do a proper man bun?
First you need long hair. Thomson says it needs to be as long as possible at the front, but once you've got that box ticked the next prerequisite is an elastic hair tie which she recommends finding in the same colour as your hair.
"Don't try too hard," she says. "Getting the look is as simple as running your fingers through the hair and looping it through a hair tie. You want to have that matte, rough texture," she says. You should put a gel through it when it's wet, she says, and tie it up when it's wet, too.
But where on the head should the crucial knot be?
"Where you place the bun is the key," Smith says. "Too low down the back of the head and it looks like a ballerina, while right on the top of the head can look a bit feminine too.
"The best place I find is just under the crown so from the front you don't see much of the bun.
"And the best buns work with a bit of facial hair as it stops it looking too girly."
So they look a bit odd. A bit "look at moi". And if you've long hair, what's wrong with a ponytail? But as Thomson says: "If your hair is long enough to tie up, it's a low-maintenance, universal look that any man can pull off."
Man buns: Would you? Do You? Love them? Hate them?