Tregear parents Renee Young and Simon Howie defied medical advice to give conjoined twins Faith and Hope a chance at life.
A spokeswoman from The Childrens Hospital at Westmead has confirmed the twins died today (May 27) with parents Renee Young and Simon Howie at their bedside.
The girls, who were three weeks old when they died, suffered from the extremely rare congenital disorder called diprosopus. They shared a heart, a body, limbs and a skull, but each had their own brain and a set of identical facial features.
After discovering the babies' condition, also known as cranialfacial duplication, at the 19 week ultrasound, Ms Young and Mr Howie were advised by doctors to consider terminating the pregnancy. But the couple, who have seven other children between them, chose to give their daughters a chance at life.
"They are breathing perfectly on their own and feeding," Mr Howie told Woman's Day shortly after the emergency caesarean birth at Blacktown Hospital.
"We have no idea how long they will be in hospital. We just want to bring them home, happy and healthy to make our family a little bit bigger and a bit more chaotic.
"Even though there is only one body, we call them our twins. To us, they are our girls and we love them."
In spite of their young age and condition, Ms Young told the magazine that the girls had "very separate" personalities.
"You have to see it to believe it. Sometimes Faith will cry and wake Hope up, who then looks sideways as if to say 'Thanks for that'," she said.
The hospital spokeswoman said Ms Young and Mr Howie signed contracts to only speak to A Current Affair and Woman's Day.