Jim Carrey has made a straight-to-YouTube video. And it's not funny at all.

The 45-year-old actor-comedian — in rare serious mode — appears in a new public service announcement on behalf of the Human Rights Action Center and the U.S. Campaign for Burma. The goal: To free Nobel laureate Aung San Suu Kyi, who has been confined by the Burmese government for 11 of the last 17 years.

"Even though she's compared to a modern-day Gandhi or Nelson Mandela, most people in America still don't know about Aung San," Carrey says in the filmed message, posted Tuesday on YouTube.

"And let's face it: the name's a little difficult to remember. Here's how I did it: Aung San sounds a lot like `unsung,' as in unsung hero. Aung San Suu Kyi is truly an unsung hero."

Suu Kyi, who is under long-term house arrest in the city of Yangon, received the Nobel Peace Prize in 1991 for her nonviolent efforts to bring down the oppressive military regime that rules over the Southeast Asian country.

The regime, led by General Than Shwe, has destroyed more than 3,000 villages in eastern Burma — forcing more than a 1.5 million people to leave their homes — and recruited more child soldiers than any other country in the world, Carrey says in his spot.

"People around the world need to come to her aid, just as they supported Mandela when he was locked up," said Jeremy Woodrum, co-founder of the U.S. Campaign for Burma, in a statement Tuesday.

"This announcement contributes to an upsurge in activism around Aung San Suu Kyi in the United States and throughout the world."