What do Scarlett Johansson, Orlando Bloom and Rachael Ray have in common?

They joined 13 other hot celebrities to support an online auction for the World Wildlife Fund. Each signed a WWF “Hotter Than I Should Be” T-shirt that was auctioned off on eBay, with  funds going to support WWF’s global climate change and other conservation initiatives.

T-shirts were signed by Kevin Bacon, Candice Bergen, Cate Blanchett, Cindy Crawford, Harrison Ford, Tobey Maguire, Paul Newman and Susan Sarandon, among other celebs. The shirts are still creating a buzz, both in the media and in Hollywood, as a unique way to spread the message that the earth is warming and to encourage individuals to take action.

“Global warming is the single biggest threat to our environment today,” says John Donoghue, WWF senior vice president. “We’re thrilled with the overwhelming celebrity support we’ve received and are confident this auction will not only garner funds for our work but will encourage individuals to take action in their own lives to stop climate change.”

Good news for OrganicAuthority.com readers: The T-shirts are made of 100% organic cotton. To purchase one (unsigned), click here.