Jake Gyllenhall stars alongside Micheal Peña, Natalie Martinez and America Ferrera star in End of Watch, a drama directed by David Ayer. The film combines both handheld camera and studio film. (Courtesy of Open Roads Film)

Michael Peña and Natalie Martinez bicker endlessly, smile at each other and throw in a few saucy winks for good measure.

But the pair, who plays a married couple in the new film End of Watch, aren’t in fact a real couple at all.

“We had mini dates where we got to know each other and that way when we got to it we’d been married for a long time, which showed through the movie that we had a very close relationship,” Martinez said in a Q&A session after the Dallas premiere of the police drama.

For Peña, the on-screen chemistry between his character, Mike Zavala, and his character’s wife, Gabby, was the least of his worries. Between sparring practices, ride-alongs with Los Angeles PD police officer and weapons training, Peña was pushed by director David Ayers to fully embody a police officer.

“We had pre-production for about four months,” Peña said. “That’s what’s different about this story. It shows you what it’s really like to be a cop.”

The movie, which chronicles the lives of LAPD police officers Brian Taylor and Mike Zavala, relies heavily on the talents and camaraderie of Peña and co-star Jake Gyllenhaal.

“[Gyllenhaal’s] dad’s a director, his mom’s like an Academy Award nominated writer, and his sister’s an actress. My brother’s a correction officer. My parents are farmers,” Peña said. “But we found [chemistry] just like how brothers are, they bicker but they love each other.”

The dramatic and emotional scenes of the movie also took a great toll on both the actors.

“We shot the ending every which way possible,” Martinez told the audience, “I was crying for like 10 hours straight but that was probably the only scene for me where I went back to my trailer and just remembered myself at the funeral.”

The movie was not without its risk, either, as most of the filming took place on location in the dangerous streets of South Central Los Angeles.

The cast members faced threats and verbal abuse from community members on their first day of camera tests.

“One of the parties in the film is actually full of real gangsters, so there were unscripted fights in the party,” Peña said.

End of Watch arrives in theaters Sept. 21. Peña is now filming as the title character in a biopic of civil-rights activist Cesar Chavez.

Martinez recently completed filming Broken City, which stars Mark Wahlberg, Catherine Zeta-Jones and Russell Crowe.