ABC News’ Nightline will air a special report tonight on the conjoined twins who were separated after a 26-hour operation.

The twins, Knatalye and Adeline Mata, shared a number of organs, making it a complicated procedure that will require months of recovery with no timetable, according to an ABC News report.

The operation, which happened at the Texas Children’s Hospital in Houston, had a number of potential complications, and surgeons spent months preparing for it.

The parents of the twins, Elysse and Eric Mata, had decided to go forward with it despite the risk because they wanted them to have a chance at having normal lives.

Nightline will air a special report detailing the procedure tonight at 12:35 a.m. ET. The Nightline team was on hand as 12 surgeons took 26 hours to separate the twins last week, and they also were able to film the Mata family as they got updates.

The twins have already beaten the odds. Conjoined twins are stillborn 60 percent of the time, and another 35 percent survive only one day. If the twins survive the first day, they have a 5 to 25 percent chance of survival, according to the report.

The parents were stunned to find out they had twins during an ultrasound, but Elysse said her heart sank when she heard they were probably conjoined.

In fact, the girls were connected from the ribcage all the way down to the pelvic region, and they shared internal organs including the liver and lungs.

Doctors tried to talk her into an abortion, but Elysse, 25, rejected that proposal.

Fortunately, the girls had their own hearts, making a separation possible.

The twins were born back in April, nine weeks premature. They stayed in intensive care until the surgery, where they remain afterward as they recover.