Who knew David Arquette** was so ripped?

On Nov. 5, the 41-year-old actor tweeted a revealing sneak peek from the set of his new movie, Orion. In the behind-the-scenes image, Arquette's muscular body is on full display, as he wears nothing more than a skimpy loincloth and metal chains. The actor -- currently dating Entertainment Tonight's Christina McClarty -- thanked his personal trainer, Jon Paul Crimi, for "helping me get in shape for my film."

"You're welcome, buddy!" Crimi replied. "We had a blast."

In the Asiel Norton-directed film, Arquette plays a hunter searching for his brother in a post-apocalyptic wasteland.

Arquette has been steadily slimming down since he got sober in early 2011, months before he and wife Courteney Cox** decided to separate. Earlier this summer, he opened up to Us Weekly about how he's maintained his weight loss.

"Don't eat too late! Don't eat too much. Nothing too big!" Arquette advised. "I do like to hike a lot -- that's my favorite! Basketball is my favorite workout! But that's a big one for people not to gain a lot of weight -- don't eat so late! Don't eat and go to bed. That's a bad combination!"

This article originally appeared on Usmagazine.com: Whoa! David Arquette, 41, Shows Off Muscular Bod in Loincloth, Chains