Seeing her boyfriend and friends trapped in the burning car, Ms Raybe Oh Siew Huey, 26, rushed forward to try and save them.
But in doing so, she suffered severe burns on about 80 per cent of her body and is now fighting for her life in hospital.
Her boyfriend, Mr Jonathan Long, 29, was driving the BMW that slammed into a Tanjong Pagar shophouse early yesterday morning.
Witnesses said the car caught fire within seconds of the crash.
Mr Akira Chan, 21, a friend of the group, told The Sunday Times that Ms Oh was not in the car at the time, but immediately rushed to the burning wreck.
"She tried to open the door and was injured in the process," he said. "She was trying to save her fiance."
Despite her efforts, Mr Long died at the scene with the four men who were with him in the car.
Ms Oh was conscious when taken to Singapore General Hospital (SGH) shortly after the crash at about 5.40am.
An SGH spokesman said she is now in critical condition in the intensive care unit.
The couple is understood to have applied for a flat recently.
Ms Oh, a former Singapore Airlines air stewardess, also sang getai on occasion. It was previously reported that Ms Oh, who was born in Malaysia, began singing getai at the age of 16 and studied at a polytechnic in Singapore.
She said in a 2013 interview with The Straits Times that when she was a polytechnic student, she performed to earn money for school fees to lighten her father's financial burden.
Getai organiser Aaron Tan, 45, told The Sunday Times yesterday that he remembered meeting her during a flight in 2019, and that he engaged her to perform in a virtual getai show last August.
"She started singing getai before becoming a flight stewardess, but mostly kept a low profile," he said.
"She had to stop for a while because of her new work commitments, but started performing again last year because of the pandemic."
He described Ms Oh as a quiet and petite person who appeared to be timid, but was actually very independent and had a big heart.
Mr Tan added: "As a getai community, we were shocked to hear of the news and pray that she recovers.
"She did what she did for love and it was a selfless act that not everybody could do. It was a commendable thing."