It will be a life-saving gift—a portion of an Ajax firefighter's liver to the son of a colleague in desperate need of a transplant.

Just before Christmas of last year, Jarrett Singer was diagnosed with Fibrolamellar Hepatocellular Carcinoma, a rare form of liver cancer. The 18-year-old underwent chemotherapy and surgery to try and get rid of the cancer, but it was unsuccessful.

“The hardest part for my wife and I was to go to recovery and to see Jarrett lying in bed and to have him look up to us and say ‘we did it,’ believing that it had happened, only to tell him that it had not,” said his father, Mark Singer.

Faced with an uncertain future, Mark Singer, who is a firefighter in Ajax, put out a call on social media and through the Ajax Fire Department looking for possible liver donors to help save his son’s life.

“With this type of cancer, it is extremely aggressive,” Jarrett Singer told CTV News Toronto. “It is very rare, only one in five million, and the surgeons that I’ve spoken to at Toronto General have only really dealt with a handful of these since they’ve been there. They don’t really know a cure yet.”

"It's a terrifying thought to know there is only one way that you can get the outcome that you want.”

Mark Singer said that no one in their family was a match, but a colleague at the Ajax Fire Department stepped up and put her name forward as a possible donor.

Nadine Young has worked as a firefighter for 14 years and said she was shocked to receive a call from the hospital that she was a match with her coworker’s son.

The decision to be an organ donor happened quickly, but Young said that when she thought about her own two-year-old daughter, she knew that she had to say yes.

“Instantly I thought, I'm doing this 100 per cent. I'm doing this,” she said. “I know they told me you can only donate once, you can only donate a portion of your liver once and I thought that people will ask me what happens if your daughter needed it and I said I guarantee, just like me, someone will step up.”

Mark Singer said he was not surprised Young put her name forward to donate, remembering years ago that she stepped forward to swap a Christmas Day shift so he could spend the holiday with his family.

"There just seems that there is no end to the heart and the care and concern and the giving that she has within herself.”

Jarrett Singer and Young met for the first time on Friday at a fire hall ahead of the transplant, which is scheduled at Toronto General Hospital for Monday.

It is expected to take about six to eight hours to remove 60 to 70 per cent of Young’s liver, and Jarrett Singer is expected to be under the knife for three to four hours.

Mark Singer told CTV News Toronto that he doesn’t know how he is going to repay Young for her act of generosity.

“How do you ever thank somebody that is doing what she is doing,” he said. “I mean, it’s an endless emotional misunderstanding—what do I do to say thank you. I mean, thank you just isn't enough.”

A GoFundMe page has been set up to help cover the costs of their recovery time.