Taylor Swift has said she is "devastated" after a fan died before her concert in Rio de Janeiro, Brazil, on Friday night.
In a statement on Instagram, the pop star said her heart was "shattered", adding: "She was so incredibly beautiful and far too young."
It came as temperatures reached 39C in the city, which is the latest stop on Swift's record-breaking Eras Tour.
Brazil has been experiencing an unprecedented heatwave during recent days with red alerts, warning of serious danger to health, issued across the country.
The star was seen handing out water bottles to fans during the concert.
"I can't believe I'm writing these words but it is with a shattered heart that I say we lost a fan earlier tonight before my show," Swift wrote.
"I can't even tell you how devastated I am by this."
Swift said she would not be able to speak about the incident from the stage because she felt "overwhelmed by grief" whenever she tried to talk about it.
"I want to say now I feel this loss deeply and my broken heart goes out to her family and friends."
She added that this was "the last thing" she thought would happen when she brought the tour to Brazil.
Swift said she had little other information about the death.
However, according to Brazilian newspaper Fohla De Sao Paolo, the fan fainted at the stadium and later died, with the cause of death being given as cardiorespiratory arrest.
In videos and pictures circulated on social media, Swift was later seen urging staff at the stadium to give water to fans during the concert.
At one point, while singing All Too Well, she was seen throwing a water bottle into the crowd.
Swift's Instagram story, commenting on the death of the fan, was posted after the show.
— Taylor Swift Updates (@swifferupdates) November 18, 2023
Brazil's Justice Minister Flávio Dino posted on X (formerly known as Twitter) that fans must be allowed to bring in water bottles to the venues.
He ordered the company organising the Eras Tour in Brazil, T4F Entertainment, to provide fans with free and easily accessible drinking water.
The minister's statement came after concert-goers were banned from bringing in their own water bottles.
The global pop sensation arrived in Brazil earlier this week for her record-breaking tour.
Rio de Janeiro's Christ the Redeemer statue was illuminated to welcome her to the country.
The pop star is due to play two more shows in Rio de Janeiro, before heading to Sao Paulo.
Swift had to cancel previously scheduled performances in the country because of the Covid-19 pandemic.
She is coming to the UK in June 2024, where she will play Edinburgh, London, Liverpool and Cardiff.
The BBC has approached T4F Entertainment, for a response.