Hollywood actor Josh Duhamel is getting into the Halloween spirit by holding a costume contest on Facebook.com.

The Transformers star is handing out charity donations to the fans who come up with the most creative outfits this year (31Oct12).

The competition includes categories for adults, children and pets, and the best entries will land $500 (£312) for a good cause.

In a post on his personal Facebook page, Duhamel writes, "Trick Or Treat?! I had so much fun last year seeing all of your Halloween costumes that I want to see them again. Please post photos of you, your kids & your pets dressed up on my wall.

"I'm going to pick my favorites in each of those categories & donate $500 (on behalf of the winners) to their favorite charities. Good luck!"