There's a conversation that Laureen Harper would like more Canadians to have around the dinner table this holiday season: organ donation.

The prime minister's wife says Canadians need to take some time over the holidays to discuss this important issue and then to head over to the Healthy Canadians website to find out how to register as a donor.

"This holiday season we were hoping to get people talking and going to the websites and signing up to be an organ donor," Harper told CTV's Canada AM Thursday from Ottawa.

"But more importantly, this is a time of year when you are with our family, so tell your family your wishes and then find out the wishes of the other people in your family."

Organ donation is one of the greatest gifts one can give, Harper said, and best of all, it's free.

"This is a gift that, come January, you won't get a credit card bill for. There's no money, and you won't feel bad about this gift. This is one of the best ones," she said with a smile.

More than 4,500 Canadians are currently waiting for donated organs, and while the vast majority of Canadians say they support organ donation, only a fraction have actually registered online to become donors.

To help Canadians register, Health Canada has created a page on the Healthy Canadians website with information about organ and tissue donation, as well as an interactive map to help Canadians contact their relevant provincial and territorial organizations to sign up.

While registering is important, Health Minister Rona Ambrose says it's also critical to communicate your wishes to your family.

"The most important thing you can do is have that conversation with your family," Ambrose said as she said beside Harper. "Tell them that you want to be an organ donor. And that will make all the difference in actually being able to save someone's life someday."

To help promote organ and tissue donation in Canada, on Wednesday, Ambrose helped launch a social media campaign using the hashtag #GiftOfLife to try to get people talking.

On Thursday evening, Ambrose and Harper will attend a gala in Toronto in support of the David Foster Foundation, which provides financial support for non-medical expenses of families with children in need of live-saving organ transplants.

Foster says the crises that lead to the need for organ donations often cause marriages to break up or sends families into bankruptcy.

"So we hope we can at least alleviate the bankruptcy part for a lot of them," he told CTV from Toronto ahead of the event.

Harper is honourary chair of this year's gala, which will include Andrea Bocelli and The Tenors, among others. Organizers hope to raise $4 million, and Harper says she's looking forward to seeing Foster at the event.

"He has been a long-time advocate for organ donation and he has helped over 800 families deal with all the expenses and things that can come with an organ donation that the health care system doesn't pay for," she said. "So David's been pushing this for a long time."