Ben Affleck has been working hard to beef-up for his role as the Dark Knight in Zack Snyder's "Batman v Superman: Dawn of Justice." According to The Hollywood Reporter, Affleck has recruited trainers from his hometown to help keep him in shape while he's on set.

Part of that group of trainers is Matt Damon's cousin, Jamie Damon. Affleck and Matt have been best friends for years. According to THR, Jamie and Matt are first cousins.  Besides Jamie, Affleck has also been working out with "sweat sergeant" Walter Norton Jr., who trained the actor back in Los Angeles and on the "Batman" set in Michigan.

Jamie and Norton are both from the Institute of Performance Fitness in North Reading, Mass. In April, Affleck's wife Jennifer Garner said that he works out twice a day and had "17-inch biceps." A different trainer, Rehan Jalali, has also been updating fans on the actor's fitness regime saying that Affleck had gained a ton of muscle.

"Update: Batman is getting Large! He's working very hard! #Dedication #Excited #DarkKnight #BatFleck #TheSixPackDietPlan," he tweeted in April but later deleted the post.

Back in March, Jalali gave another quick update posting that "Operation Biggest/Leanest/Baddest Batman Eva is on schedule! #DarkKnight."

Affleck isn't the only on getting in tip-top shape to play a superhero. Gal Gadot, who was cast as Wonder Woman in "Dawn of Justice," previously told E! News exactly what her early morning workouts included.

"I just keep active. Everything that challenges me, everything that I feel like doing," she said. "It's not like I'm only TRX or Pilates. I do sports."

Gadot also said she has been sticking to a very strict diet but there are times when she will allow herself to stray and indulge in one of her cravings.

"I try to eat healthy," she said. "But sometimes though, I eat cheeseburgers. That's good for the soul. I make sure to balance everything out. I drink tons of water."

"Batman v Superman: Dawn of Justice" is due out May 6, 2016 and will have a box office showdown with "Captain America 3."