Facebook users now have the option of letting their friends know they're an organ donor.

Facebook CEO Mark Zuckerberg announced Tuesday that people in the United States and United Kingdom can enroll as organ donors through links on the site to official registries.

Users also have the option of listing "organ donor" on their Facebook timeline, just like they would share their birth date or relationship status.

Zuckerberg said he was inspired after seeing Facebook users utilize the social networking site to rally support for tornado victims in the U.S., as well as disasters like the Japan earthquake and tsunami.

He added that Facebook is a powerful tool for communication and problem solving.

More than 110,000 patients in the U.S. are waiting for an organ transplant.

Zuckerberg hopes that allowing Facebook's nearly 1 billion users to share their organ donor status will help raise awareness.