Taylor Swift is mourning one of her fans after announcing that they died prior to her show in Brazil on Friday.

“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. I can’t even tell you how devastated I am by this. There’s very little information I have other than the fact that she was so incredibly beautiful and far too young,” she wrote on Instagram following her Eras Tour concert in Rio de Janeiro.

She continued: “I’m not going to be able to speak about this from stage because I feel overwhelmed by grief when I even try 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. This is the last thing I ever thought would happen when we decided to bring this tour to Brazil.”

Swift didn’t provide additional details in her announcement although Brazil’s Folha de S.Paulo newspaper reported that a 23-year-old fan – Ana Clara Benevides – fainted and was treated at Rio’s Estádio Nilton Santos before being sent to a local hospital, where she later died.

Her cause of death was cardiorespiratory arrest, the newspaper said.

Swift’s Rio show occurred on a night where fans faced extreme temperatures amid a dangerous heat wave in Brazil.

Officials reported around 1,000 fans fainted at the event while some concertgoers vomited and suffered from severe dehydration, according to Folha de S.Paulo.

The concert occurred just days after Rio saw its heat index – a combination of air temperature and humidity – hit 58.5 degrees Celsius (137 degrees Fahrenheit) on Tuesday, The Associated Press noted.

It marked the highest-ever recorded heat index in the city.

Videos shared on social media Friday showed fans calling for “water” at the venue as Swift, who noticed the chants from the stage, appeared to point out the concertgoers to staff.

“Sorry, it’s just very hot so if somebody says they need water when it’s this hot, they really need it,” she said.

One clip shows Swift, in the middle of performing a song, tossing a water bottle into the crowd while another shows Tree Paine, Swift’s publicist, checking in on a fan as staff surrounded them.

HuffPost has reached out to T4F Entretenimento – the company reportedly responsible for the tour in Brazil – and the venue for comment.