Mark Ruffalo Uncovers Surprising Truth About FBI Agents That Changed His Perspective Forever

If you could eat your way into the mind of an FBI agent, would you start with a Philly cheesesteak or a slice of psychological insight? That’s exactly the sort of oddball preparation Mark Ruffalo brings to his latest turn in HBO’s Task, where he’s not just chasing down a string of high-octane robberies in Philadelphia—he’s learning what makes an agent truly exceptional (hint: it’s not the badge, but empathy). As Ruffalo packs on pounds and wisdom under the watchful eye of a retired Bureau pro, behind-the-scenes stories emerge that are as savory as the city’s legendary sandwiches . The result? An unlikely crime saga where you might root for both sides—if only the pop-and-lock tension would give. If you’ve ever wondered how a single dad, a rubbish collector’s gig, and a sandwich-laden stakeout could collide in an HBO drama, well, you’re in just the right place . Hungry for spoilers? You’ve been warned . LEARN MORE

Warning: spoilers ahead

Mark Ruffalo has revealed the one thing he has learned about FBI agents while working on his new movie.

The actor, 57, who stars as FBI agent Tom Brandis in the new HBO series, Task, recently explained how he prepared for his role, revealing that he learned some pointers from the now-retired FBI special agent, Scott Duffey.

Task is set in Philadelphia and follows FBI agent Brandis as he leads a task force to try and put a stop to a string of violent robberies.

It also stars Tom Pelphrey as Robbie Prendergast, a single dad who’s trying to give his family a fresh start.

While working as a rubbish collector, Robbie scopes out a number of properties to rob, and eventually ends up being suspected by the FBI.

“The tension of the story is that you care about both of these guys,” screenwriter Brad Ingelsby told The Hollywood Reporter.

“You want Robbie to get away and you want Tom to get a win. But you know that can’t happen.”

Ruffalo spoke about starring in the series (Kristina Bumphrey/Variety via Getty Images)

The cast also includes Emilia Jones, Jamie McShane, Sam Keeley, Thuso Mbedu, Fabien Frankel and Alison Oliver.

To prepare for the role, Ruffalo explained how he spent a lot of time in Philadelphia, mainly eating a lot of sandwiches, but he also learnt something invaluable from Duffey.

Speaking to PEOPLE at the premiere for Task, he explained: “I learned that the best FBI agents have a lot of empathy.”

He also added: “I ate a lot of Philly cheesesteak sandwiches. I just put a bunch of weight on!”

Ruffalo in new HBO series Task (HBO)

Ruffalo arrived at his first costume fitting having been requested to put on 30-40 pounds for the role.

Speaking to The Hollywood Reporter, Ruffalo explained that the designers fitted him with a pregnant belly to achieve his look.

“Then when I went in for my camera test, the producers saw me and their jaws hit the ground,” he said.

“They were like, ‘We don’t want to see Mark Ruffalo like this!’ But I think it’s these impediments that make Tom such a dynamic FBI agent because he makes up for it in other ways. And, I did come to find out from Scott Duffy, our technical advisor from the FBI, that people like Tom are good agents because of their compassion with people and ability to interview them.”

Pelphrey stars as Robbie (Taylor Hill/FilmMagic)

In the UK, Task is available to watch on Sky Atlantic and NOW.

While it only dropped this week, it’s so far bagged an 89 percent Tomatometer score and a 71 percent Popcornmeter rating.