When actress Nia Long joined the cast of NBC's Third Watch (Fridays, 9 pm/ET) last year, she was thrilled to play policewoman Sasha Monroe right on New York City's mean streets. In fact, the 34-year-old Brooklyn native looks so convincing, passersby sometimes mistake her make-believe for reality.

"[I love] running around the streets of New York in a cop uniform with a gun," Long happily tells TV Guide Online. "[Recently,] I was on a long break. I had my uniform on, but I was on my cell phone and was wearing flip-flops. My shirt was out, but I had my gun belt on. And this woman, someone hit her car and ran.

"She's like, 'Miss, you are police officer, right?' I'm like, 'No, what are you talking about?' I

forgot that I had the uniform on. She's like, 'I need someone to call the police.' I'm like, 'Well, call 911, I'm not a [real] cop.'"

Aside from these occasional moments of confusion, Long enjoys her work atmosphere. "People in New York City love the show. We have so much support and it is really hard work," the petite gal says. "And at Third Watch, those people are my family."

Speaking of kin, Long left acting a few years ago to have her now 3-year-old son. Between Third Watch and her current big-screen role in Alfie, she's definitely accomplished her comeback. "Taking a break and coming back to this is a true testimony to my faith," she sighs, "because not many people walk away and say, 'Bye, I'll be back.'"

Working alongside the dreamy Jude Law helped make the transition back to work easier — even if she's just one of his many lovers in the film. "He was just great," she smiles. "None of the girls actually saw each other. It was like I had him for two weeks and then Marisa [Tomei] had him for two weeks. We shared him.

"One day, I left and came back and said to Jude, 'How are you feeling? You've had all these women in a short period of time. Are you OK?' He's like, 'It is like eating too many chocolates.' It was a perfect way to describe it."