Local police say the singer died after falling from the third-floor balcony of his hotel on Wednesday evening.
Here’s what we know so far.
Reports claim the star singer fell to his death from a room on the third floor at CasaSur Palermo Hotel in Argentina’s capital Buenos Aires.
What was his cause of death?
Head of the local emergency services Alberto Crescenti told the Buenos Aires Times that “there was no possibility” for emergency personnel to save Payne’s life.
Crescenti said he had “very serious injuries”.
“He had very serious injuries that caused his death, such as a fracture at the base of the skull,” he said.
The fall from the balcony is understood to be around 13 to 14 meters.
Why was Payne in Argentina?
Payne was holidaying in Buenos Aires and was staying at CasaSur Hotel in the affluent neighbourhood of Palermo.
Earlier this month he attended a concert in Buenos Aires for former bandmate Niall Horan.
Reports claim Cassidy left Argentina on October 14.
He was posting on the social media platform Snapchat in the hours leading up to his death, sharing details of his holiday.
“It’s a lovely day here in Argentina,” he said in a video posted to Snapchat.
Payne rose to fame as one of five members of popular UK boy band One Direction.
He debuted as a singer after auditioning for British TV series X Factor in 2008 aged 14.
He was later eliminated from the series but encouraged to re-audition for the show when he was older.
Payne re-auditioned as a solo artist in 2010 and was later grouped with Zayn Malik, Harry Styles, Louis Tomlinson and Niall Horan to form a boy band.
One Direction placed third on the show and quickly rose to global stardom thereafter.
The band was signed to Simon Cowell’s record label Syco Entertainment in December 2010.
Their debut single What Makes You Beautiful was released in September 2011 and reached number one in several countries.
One Direction became the first UK group to have their debut album reach number one in the United States in March 2012, following the release of Up All Night.
The band went on to release three more albums and embarked on four world tours, with their success often compared to that of Beatlemania of the ’60s.
Payne was known as one of the main songwriters in the bans and was credited with co-writing more than half of the songs on the band’s third and fourth album.
The band announced a hiatus in December 2015, nine months after band member Zayn Malik left the group, citing his wellbeing.
Payne went on to have a career as a solo artist, releasing his first single ‘Strip That Down’ in 2017.
In March he released his first song since 2021, Teardrops, which peaked at number 43 on UK charts.
Last month NME reported Payne had postponed the release of his second solo album, indefinitely.
Payne leaves behind a seven-year-old son, Bear Grey Payne, who he shares with former girlfriend and pop singer Cheryl Cole.
Payne became engaged to model Maya Henry in 2020, with whom he had an on-off relationship until their split in 2022.
Henry reportedly took legal action against Payne just two days ago, accusing him of repeatedly contacting her.
In a video posted to TikTok, Henry detailed allegations about Payne’s attempts to reach her.
The Strip That Down singer was born in Wolverhampton in England’s West-Midlands.
He is also survived by his parents Geoff and Karen Payne and older sisters Ruth and Nicola.
Payne’s history with mental health and addiction
Payne was open about past struggles with drug and alcohol abuse, as well as navigating issues with his mental health .
He publicly spoke about finding it difficult to regulate his alcohol intake during the peak of his fame with One Direction.
“The best way to secure us, because of how big it got, was to lock us in a room,” he said.
“And, of course, what is in the room? A minibar.
“At a certain point, I just thought, ‘Well, I’m going to have a party for one’.
“That just seemed to carry on throughout many years of my life.”
Payne told the podcast he hit rock bottom after a “booze and pills phase” that lasted several years.
He revealed he turned to alcohol again during the COVID-19 pandemic while isolating at home.
“It was just getting earlier and earlier. Easier and easier to go to,” he said.
“There were no boundaries. So, if you’re on Zoom you quite easily hide that you might be a little bit tipsy at the point you shouldn’t be.”
In 2023 he spent nearly 100 days in a Louisiana rehab facility recovering from alcohol addiction.
Payne has discussed struggling with anxiety, depression and suicidal ideation on several occasions.
In July 2023 he posted a candid video to Instagram, telling fans he’d been diagnosed with “a couple of conditions”.
“Not to go too much into detail, but one of them that I have, basically, there are a lot of manic things in my life which you guys saw,” he said.
“But, the other side of it, that kind of feels like when I would lose my sobriety, in these moments that I was super low.”
He went on to thank the “amazing people” around him for supporting him and encouraged fans to seek help for their mental health.
“I just wanted to put this out here anyway, because I know there are probably a few people who have the same thing, maybe you don’t even know it sometimes.
“But, just so you know, you’re not the only one.”
At this stage it is not known whether alcohol or drugs were involved in Payne’s death.