Is she a good cop, or a bad cop? The first trailer for Jennifer Lopez's forthcoming NBC cop drama "Shades of Blue" has finally arrived, and it is action-packed.

Lopez plays a New York City police officer named Harlee Santos who is "known to improvise" her "creative police work."

The trailer opens up with Lopez's character taking the law into her own hands and illegally busting a drug dealer, which leads to her being arrested by the FBI. She is convinced to go undercover for the FBI as an informant in order to protect her daughter.

Ray Liotta also co-stars as Lopez's boss, Lt. Matt Wozniak, who finds out someone on his team is spying for the FBI.

"There's a rat!," he yells. "A aat! An FBI informant on my team!"

The pilot is directed by Barry Levinson, who won an Oscar for directing "Rain Man," according to Entertainment Weekly. The new show received a straight-to-series order of 13 episodes last year.

"Who we think we are and who we turn out to be... are they ever the same?" Lopez asks in the trailer. 

"Shades of Blue" is set to air this January on NBC.

Check out the first trailer below.