'Vampire Diaries' star Ian Somerhalder joins Gisele Bundchen and Don Cheadle for UN Environment Program

As if "Vampire Diaries" star Ian Somerhalder didn't have enough on his plate between saving the world with the Ian Somerhalder Foundation off-screen and wooing Elena on-screen, he's now taken on a new title as a United Nations ambassador for their upcoming World Environment Day.

Last year, Gisele Bundchen and Don Cheadle joined forces to encourage people to contribute to clean-up progress and environmental causes on a specific day, registering their activities in order to break a record. Somerhalder jokes that he joined in this year because he "couldn't decide between Team Don and Team Gisele."

"So as the new kid on the block, I am relieved that this year, we're all working together," he says. Check out the video below to learn more about the initiative -- and about how you can win one of five cars (fuel-efficient, of course!) that will be given to winners.

"Who knew being an environmental warrior could be so cool?" Somerhalder asks.