Harry Styles downed a 'shoey' - a divisive Australian trend

In front of 30,000 screaming Australian fans on Monday night, British pop star Harry Styles raised a sweaty sneaker full of water to his lips and drank.

"This is one of the most disgusting traditions I've ever heard of," he told the Perth stadium, grimacing before downing the drink to deafening chants of 'shoey, shoey, shoey'.

Post-swallow, Styles told the raucous crowd he felt "like a different person".

"I feel ashamed of myself," he said, shaking his head. "I'll be discussing this with my therapist at length. At length!"

Styles is just the latest international star to be subjected to the questionable Australian trend that is the shoey: drinking a beverage, usually alcoholic, from a shoe.

F1 driver Lewis Hamilton, actor Sir Patrick Stewart and a slew of musicians - including rapper Post Malone, Machine Gun Kelly and country singer Kasey Musgraves - have partaken while visiting the country, usually at the insistence of Aussie supporters.

But the trend is divisive. Many Australians say it is tired, gross and "blokey"; an embarrassing thing for the country to be known for.

Others say it's a harmless bit of fun rooted in Australian culture - which values self-deprecating humour and a sense of egalitarianism.

No-one is sure where the shoey originates from.

"Like any cultural tradition, a few people try and claim it," Liz Guiffre - a communications lecturer at the University of Technology Sydney - told the BBC.

There are rumours soldiers did shoeys during the World Wars, as did Russian ballet stars long ago.

But the earliest shoey Ms Guiffre has found photo evidence of took place in 1951. American actress Tallulah Bankhead was captured sipping champagne from her heel during a press conference at the Ritz Hotel in London.

But what started as a show of "opulence" at some point evolved into something "silly" in Australia, Ms Guiffre says.

Mark Gwynn, who has been researching the word to add to the official Australian National Dictionary, says the shoey is a fairly recent phenomenon in Australia.

The first references he can find dates back to 2010, when the shoey was associated with the Australian punk music scene, but was also a feature at parties and sporting matches. It's typically done to mark a celebration.

"It's a triumph over adversity thing… the whole idea that I've just done this really hard thing and I'm going to drink out of the shoe that got me there," Ms Guiffre says.

But both researchers say the shoey - the word and the act - were undoubtedly popularised in 2016 by Australian F1 star Daniel Ricciardo. He made it his trademark race celebration and boosted its global exposure.

It has only exploded in popularity since.

Australian golfer Hannah Green earlier this month celebrated with a shoey after winning her first tournament on home soil, and Nedd Brockman - who ran the width of Australia last year - finished his run with a sock-flavoured cocktail.

Observers have proposed that the shoey reflects Australian values.

The humble act plays into Australia's famous dislike for "tall poppies", says Ms Guiffre.

"There's nothing dignified about it… You're saying 'I'm not up myself'. We love people to win, but… we don't want people too over the top or too proud."

It's also a homage to Australia's sense of humour, adventure, and drinking culture, Mr Gwynn says.

"This is not violent. It's not inherently sexist, or racist or anything. It's an easy-going, 'out there' bit of fun."

But many Australians find it gross. It's a stupid trend that's outlasted its shock value, those critics say.

Mackenzie tells the BBC he recoiled watching Styles down shoe juice on TV. The 24-year-old - who calls himself a "reformed alternative vessel enthusiast" and is too embarrassed to provide his last name - says the trend has not aged well.

"I'm not sure if I haven't ever done a shoey, or if I've managed to effectively suppress the memory of doing a shoey."

"[But] shoeys are out, basic hygiene is in."

Although the risk is pretty low, research has shown that a shoey can host an array of harmful bacteria like those that cause staph infections.

Critics also say the shoey panders too much to stereotypes which don't reflect modern Australia.

They say it is "blokey", "lowbrow" and fuels the stereotype that Australians are bogans - local slang for an uncouth person of low social status.

"There's been some criticism online saying it's a bit undignified and are we really treating an international guest properly and all that stuff," Ms Guiffre says.

"But, I mean, nobody made him do it. I think Harry's going to be okay. He's in beautiful Gucci shoes that are probably cleaner than coffee mugs that you and I have on our kitchen counters."

Brooke Littler, who was standing in the front row of Styles' performance on Monday night, was absolutely shocked by the star's cup of choice.

"I can't believe he actually did it. I didn't think he was going to."

But she wasn't horrified or embarrassed.

She says shoey demands have been a regular staple at most concerts she's been to in recent years, and though the singer clearly "hated" it, she thinks he deserves credit for braving the trend.

"I think it's pretty disgusting and I don't understand why it's a thing… but I love watching other people do it."

You won't catch her participating in it any time soon though.

"Honestly, the only way I would do one is if Harry Styles asked me to."