Twin sisters Bellanie and Ballenie were born conjoined at the lower back.
The girls surprised their parents, Laurilin Marte and Marino Camacho, who were expecting twins, but were unaware that the siblings were conjoined.
However, their parents soon became concerned after doctors revealed that the smaller of the twins (Ballenie) has a congenital heart condition and warned that without treatment, she may die.
After seeking a number of medical opinions, the girls were taken to Maria Fareri Children's Hospital in New York, where staff took more than three months to prepare for their life-saving surgery.
During this time, medical teams conducted numerous practice sessions to ensure the complex procedure would go as planned.
On January 17, the girls underwent a mammoth 22-hour surgery where they were successfully separated.
Accordingly to TODAY, the medical teams broke into a round of applause at the moment of separation.
While it is unclear whether the sisters will ever walk, doctors are optimistic about their futures.
They will celebrate their first birthday on February 4 and if there are no complications, they could be able to return home with their parents in just a few short months.