When a Milton, Ont. woman was told she had one year to live if she couldn't find a liver donor, her young neighbour stepped up and saved her life.

During routine blood work in 2009, 39-year-old Renee Ly was diagnosed with primary sclerosing cholangitis, a rare liver disease. The disease attacks the bile ducts, leading to liver damage and eventually liver failure.

Most patients with PSC require a liver transplant after 10 to 15 years, according to Toronto Western Hospital's liver clinic. However, doctors were unsure how long Ly had the disease before it was diagnosed.

Then last July, Ly got home from a vacation feeling ill. She was told she urgently needed an organ transplant.

Ly put her name on the donor list in September 2013. She was told she had one year to live.

"You have to go through a screening, so when you get the final word that you've made it, it's great, but then it starts to sink in: Am I going to get the call in time? Without a live donor, you have to wait for a deceased donor," Ly explained in an interview on CTV's Canada AM on Wednesday.

What Ly didn't know was that, without telling anyone, Ly's 21-year-old neighbour Erica Tomlinson went to a liver clinic for testing when she first heard about the disease. The process includes medical history questionnaires, blood samples, X-rays, full-body scans and consultations with surgeons.

The odds of being a match are one in six, and Tomlinson found she was a match to her neighbour.

When Ly got on the donor list, Tomlinson made her decision. "We're doing this, let's get it done," she said.

Initially, Ly had a hard time accepting her neighbour's offer: "It's very hard to accept, from a recipient's point of view, that somebody out there wants to put themselves at risk to save your life."

Ly and several doctors warned Tomlinson of the risks of surgery, including infection and internal bleeding, but the event planner booked the surgery anyway.

"It is a risk to my life, but if I can save Renee's life and her whole family then why wouldn't anybody?" Tomlinson told Canada AM. "I'm young, I have nothing to hold me back and I have my health, so if I can do it, I'm going to do it."

The women went in to surgery at the Toronto General Hospital on Nov. 20, 2013. Tomlinson gave 70 per cent of her liver to Ly. She said her liver will regrow to 100 per cent of its original size in 12 weeks.

Two months later, Ly said she feels reborn. "I'm not even finished recovering yet and I haven't felt this good in years."

The women started a Facebook page to help raise awareness of live liver donations, and are touched by the number of people interested in their story.

Ly and Tomlinson have become advocates of blood and organ donation since their experience, urging the public to apply to be donors through provincial governments.

Despite a thin, 20-centimetre-long scar across her stomach, Tomlinson said she feels "fantastic."

"I'm so happy to have my neighbour. I still need to borrow a cup of sugar and milk now and then, so I need her there."

With files from CTV's Canada AM