(Cover) - EN Movies - Bradley Cooper says he is slowly turning into Robert De Niro.

The two actors appear in the new movie Silver Linings Playbook and previously worked together on sci-fi thriller Limitless.

The 37-year-old says his co-star is so “infectious” he can’t help behaving like him.

“To this day, I can’t believe [I’m friends with Robert]. He’s infectious,” Bradley gushed to ShortList.

“You know when you’re with some of your friends and you just start to act like them? That’s what he’s like. When you’re with him, you find yourself just starting to adopt some of those mannerisms through osmosis. I draw the line at going to get a Mohawk, though.”

Bradley plays bipolar-sufferer Pat Solitano in dark comedy Silver Linings Playbook, while Robert portrays his father.

One of the toughest aspects for Bradley was the physical exertion required on set.

“My God, there was a lot of running. I severed my Achilles tendon six years ago playing basketball. Every day I just thought, ‘Oh my God, I hope this isn’t the day something pops,’” he recalled.

“I was in pretty good shape by the end of the shoot. I loved it – think about it, you get up in the morning and go to work and you get to wear a garbage bag, or a football jersey. You have a crew cut, and don’t shave, and all you do is run. It was nice being low maintenance.”

Silver Linings Playbook also stars Jennifer Lawrence and hits cinemas worldwide from this month.