Matt Damon's Cousin is Training BFF Ben Affleck for 'Batman vs. Superman: Dawn of Justice'!

Matt Damon is all sweaty after getting in a good workout at his gym on Wednesday (June 4) in Beverly Hills, Calif.

The 43-year-old actor’s first cousin Jamie Damon has just been hired by Ben Affleck to train him up for his role as Batman in Batman vs. Superman: Dawn of Justice, THR reports.

Jamie, along with trainer Walter Norton Jr. and a group of other sweat sergeants, have been on set with Ben running drills with him to prep him for the Caped Crusader.

Matt called Jamie “a stud of a trainer.”

10+ pictures inside of Matt Damon leaving the gym all sweaty…