That's what funnyguy Jonah Hill had to do in the about-to-be-released sports drama, Moneyball.
So when we caught up with Hill at the VMAs, we had to ask: Which actor did Hill find more intimidating?
"It was scarier to work with Phil, because his character didn't like me in the movie," Hill said. "Brad and I are the two leads of the movie and Phil, he doesn't like us in the movie. He doesn't like what we represent."
Moneyball is the real-life story about Oakland A's manager Billy Beane's (Pitt) attempt to revamp the disgraced baseball team with the help of his assistant general manager (Hill).
Hill echoed what so many other celebs have told us about working with Pitt.
"He's fantastic," he said. "He's so giving. He's just, like, a guy you look up to for so many reasons. He's the coolest guy! He started playing pranks on me like right off the bat." Hill declined to say exactly what Mr. Pitt did, but we imagine whoopee cushions were not involved.
Work aside, we couldn't not compliment Hill on his very slimmed-down and much healthier appearance.
Asked what he's been doing to keep the pounds off, he simply said, "Just eating healthy, running and doing push-ups."