Facebook users will soon be able to let their friends know whether they are registered to be organ donors -- a change that some say could lead to an explosion of new donor sign-ups.

Starting soon, Facebook users already signed up as organ donors will be able to add their donor registration status to their profile page -- now known as their Timeline – by clicking on "Life Event" and then "Health & Wellness."

They can then use the "Organ Donor" tab to mention when they signed up, and why they did it.

Those who haven't registered will be able to click on a link to official registries in their state or province

But the new feature is not yet available to Canadians. It's being rolled out to Facebook users in the United States and the U.K. first, will plans to expand the feature to other countries soon.

Facebook CEO Mark Zuckerberg announced the change on "Good Morning America" Tuesday. He said the hope is that the move will encourage more people to register while also spreading awareness about the need for organ donors.

Zuckerberg said his friendship with Apple Inc. co-founder Steve Jobs, who received a liver transplant before he died last year, helped spur the idea. So did talks with his girlfriend Priscilla Chan, a medical student studying pediatrics.

"People are using the same social tools that they're using just to keep in touch with people on a day-to-day basis to solve these important social issues," Zuckerberg told host Robin Roberts.

"So, we figured, okay, well, could we do anything that would help people solve other types of issues, like all of the people who need organ donations in the world? And we came up with this pretty simple thing which we're hopeful can help out just in the same way that people have done all these other things."

Dr. Andrew M. Cameron, the surgical director of liver transplantation at Johns Hopkins Hospital, told The New York Times that he thinks that the change could compel millions of people to shift their donation status overnight.

"This is going to be an historic day in transplant," Cameron said.

Facebook currently has about 900 million registered users around the world.

B.J. Fogg, the director of the Persuasive Technology Lab at Stanford University, said the prominence of one's organ donation status on Facebook could trigger more to make a decision on their wishes for organ donation.

"If you see all your friends do it, or have the illusion all your friends are doing it, it sets up an expectation of sorts and it may become a social norm," he told the Times.