J K Simmons gets pumped for 'Justice League'

Actor J K Simmons is putting on muscles in preparation for his upcoming turn as the police chief of Gotham in "Justice League".

Aaron Williamson, a former Marine and competitive bodybuilder who becomes Simmons' personal trainer, revealed the actor's transformation in a photo he posted on Instagram on June 3.

In the photo, Simmons can be seen working out in a gym. Lifting weights and using an arm-blaster, he showed off his impressive physique.

"Every time we train together I forget he's 61 years old. So much respect for this guy," Williamson captioned the picture, adding the hashtags #JKSimmons and #OldmanCranking.
 

The bodybuilder trainer, who is also a personal trainer to Dwayne "The Rock" Johnson and James Marsden, explained that the "Dark Skies" actor's training motivation was to keep himself healthy.

"His goal was to have 'sick arms,' " the trainer explained . Later, Simmons started to fall in love with fitness.