The 39-year-old actor, who is married to The Black Eyed Peas star Fergie, is handing out charity donations to the fans who come up with the most creative outfits this year, reported Showbizspy.
The competition includes categories for adults, children and pets, and the best entries will land USD 500 for a good cause. In a post on his personal Facebook page, Duhamel wrote, '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 and donate USD 500 (on behalf of the winners) to their favorite charities. Good luck," he added.