Ben Affleck, 39, and best pal Matt Damon, 40, are sporting new looks lately for movies they're filming. Ben is working a beard and a shaggy 'do for his new '70s flick Argo, while Matt shaved his head for the 2012 action flick, Elysium.

Both men have been heartthrobs since their late 20s, when they burst onto the Hollywood scene with Good Will Hunting.

Now, the hotties are hitting the big 4-0 and trying on these new styles, and we've gotta know -- who is looking better? Vote in our poll below!