When Matt Damon agreed to sign on for director Neill Blomkamp's dystopian scifi flick "Elysium," he was given a very clear idea of how much gym time he'd need before filming. 

"He actually had a picture with my face tacked onto this guy with this body, and they literally hired me a trainer and I went to him with the picture," Damon said. "It was four hours a day in the gym -- and I’m not 26 anymore, but I got in shape.”

Damon recently told People that because he loves to eat and drink, finding the right motivation to get in shape can be very difficult. Nevertheless, Blomkamp's image provided the right motivation. "I went okay, this is definitely worth it," Damon said.

"Elysium," which opens this week, takes place in the year 2154. The wealthy live in a luxurious space station free of crime, disease, hunger and poverty called Elysium — while the rest of humanity scrapes by on a polluted and ruined Earth. When the character played by Matt Damon discovers that he has less than five days to live, he hatches a plan to travel to Elysium to cure his illness and ultimately balance the scales. 

As mentioned back in April, Damon counts two weeks of the "Elysium" shoot as being the toughest of his career — in particular because the crew was filming within Mexico City's Bordo Poniente landfill, the world's second largest dump.

"(We had to) literally eat s**t ... It was explained to us that, like any dump anywhere in the world, the dust is actually comprised largely of fecal matter," he shared. "After they tell you that the dust is all fecal matter, then they see what you're doing (on set), they go, 'You know, not your dust ... all the other dust!' So, at the end of every day, as we'd wipe this stuff off, we'd be basically throwing these s**tty towels at each other."

Check out a trailer for the film below. 

Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.

How Matt Damon bulked up for 'Elysium'
Actor says director Neill Blomkamp was very specific about how he wanted the character's physicality portrayed on screen.