He's always been in great shape, but Mark Wahlberg was spotted on set this week looking better (and bigger) than ever!

The 40-year-old is in Miami shooting his new flick "Pain and Gain," in which he plays a bodybuilder. The actor certainly seems to have taken his training seriously -- his size rivals that of costar Dwayne "The Rock" Johnson!

Not that we ever really need an excuse, but we thought this was the perfect opportunity to dust off our Fit & Over 40 photo gallery! Hotties like George Clooney, Robert Downey Jr, Simon Baker and Rob Lowe only seem to get better with age, and believe us, we've noticed.

Click below to see shots of your fave over 40 dudes who are looking fit and fine.