(Cover) - EN Movies - Michael Peña feared he wouldn't be able to convincingly portray Jake Gyllenhaal's "brother from another mother" in their latest film.

The pair star as Los Angeles Police Department (LAPD) partners and best friends in action-drama End of Watch. Michael found bonding with his co-star difficult at first.

"It's so weird hanging out with this guy knowing he's going to be like your brother from another mother," he told British newspaper The Guardian.

"It puts a lot of pressure on you. David [Ayer, director] didn't want us to be actors. He's like: 'You guys will die for each other.' I'm like: 'Oh, sh*t. How am I gonna do this?' We spent so much time together. We were always sparring. And when somebody punches you in the face you realise, like, I'm gonna fight! It wasn't like any Hollywood sh*t; it was really getting down and dirty."

Jake says after five months of researching together, both he and Michael could really bond. The pair went on ride-alongs to ensure they could properly portray cops and the long shift hours brought them together.

"It'd take me a couple of hours to get to sleep. You're not really involved. Which makes you feel weirdly even more alone. Which is where Michael and I could connect," he revealed.

"We would see things happen and say: well, our job is to observe it and then, absurdly, to fake it. Mike and I will always be close because of that."