Rihanna -- I Want to Help Expose Joseph Kony as an Evil Bastard

TMZ has learned ... Rihanna has reached out to the Invisible Children organization and has expressed an interest in creating a video to help raise awareness about an evil S.O.B. named Joseph Kony.

Kony is quickly becoming a household name ... thanks to a viral YouTube video that exposes the Ugandan warlord as the bloodthirsty leader of a child army and child prostitution ring.

In the YouTube video, producers beg for celebrity support to raise awareness and showed a picture of Rihanna, in an effort to get her involved.

TMZ has learned ... Rihanna saw the video and was so moved by the story ... that she called the organization this week and set up a meeting, hoping to create another video to keep the momentum alive.

We're told both sides are hoping to complete the project ASAP.

Stay tuned.