The actor packed on the weight for his new dark comedy, The Lobster

By Gillian Telling
Updated May 11, 2016 12:40 PM
Credit: Mike Pont/FilmMagic

Colin Farrell says it wasn’t hard to gain 40 lbs. in just two months for his new role as a father of two in the satirical comedy The Lobster– it just meant he had zero portion control.

“I just ate and didn’t move for a while,” Farrell, 39, tells PEOPLE of how he packed on the pounds. “It was stuff I normally eat, but just a lot more of it. People talk about portion control – there was no control!”

As soon as the film wrapped, Farrell dedicated himself to losing the extra weight.

“It took me two months to lose it,” he says. “I’m bit demented that way, discipline-wise. If I have a goal, that is. I can actually be a bit undisciplined with my life stuff. Unless I have something to task myself with!”

For more on Farrell, pick up the new of PEOPLE, on newsstands Friday

The film, which is playing now, is set in a city where single people must fall in love within 45 days or else be turned into an animal and released into the forest.

“I was confounded by it,” Farrell says of the storyline. “It’s exploring very real themes within the world we live in.

So if he had to turn into an animal? “I’d be a bird,” he says. Either a falcon or a seagull, depending on if I want to be an apex predator or just something that lives near the shoreline.”