Secrets, lies and murder: those are the ingredients in a tense thriller with Oscar-winner Halle Berry, Giovanni Ribisi and Bruce Willis. Alan Silverman has a look at Perfect Stranger.

Halle Berry stars as Rowena, a resourceful New York investigative reporter whose specialty is going undercover - assuming a fake identity - in order to get the story. But when a friend is murdered, Ro finds clues that lead her to believe the killer is Harrison Hill, a powerful business tycoon.

To gather evidence, Ro masquerades as a temporary office worker named Catherine and gets herself a job on Hill's staff. A notorious womanizer, he quickly notices the sexy, flirtatious office clerk ...just what she wanted him to do ...and the game of cat-and-mouse is on.

Halle Berry in scene from Perfect Stranger

Halle Berry says the role of someone who is playing roles intrigued but also frightened her.

"She is very complicated and reading the script, it took so many twists and turns and there were so many twists and turns and there were so many revelations," Berry says, "by the time I got to the end, not only was I just wrung out, but I was shocked and I thought "Oh my God, I need to go back and read this again ...which I did. Then, when I thought about making the movie I thought this is going to be really challenging to be able to lead the audience in a direction that I want them to go. I didn't know if I'd be able to do it. I felt instantly scared to death of it, so I knew I had to do it.

"I think the beauty of Ro is that she was smart enough to know how to use her sexuality," adds Berry, "and I think that a smart woman knows that. It's part of the power that we wield as women and I think it's okay to use all parts of us when we need to ...and I love being a woman for that reason."

Bruce Willis in scene from Perfect Stranger

Bruce Willis co-stars as the philandering advertising executive Hill.

"You seldom get parts where you get to flirt so unabashedly ...and I did. It's not a hard day at the office when you have to go to work and flirt with Halle Berry," he says.

But to make him believable as a murder suspect Hill must also appear to be dangerous, especially when he accuses Berry's character of spying for a rival ad agency.

Berry says her character had to be good at pretending to be someone else ...but not too good.

Bruce Willis and Halle Berry in scene from Perfect Stranger

"When Ro was pretending to be Catherine I had to act well enough so the Bruce Willis character would believe that I was this little tarty temp that was there just for his pleasure; but I also had to be careful not to act so well that the audience would forget that I was acting ...that she's really someone else," Berry explains. "That was a fine line. There were some takes where (director) James Foley would say 'cut!' and I would think 'what did I do? Wasn't that good?' He would say 'lest I remind you again, Ro does not have an Oscar. You have to make it worse. You can't be that good of an actor.' So that was my challenge: to try to act well, but not so good at the same time."

The cast also features Giovanni Ribisi as Ro's tech-expert sidekick. He says each character has secrets and the object is to keep the audience guessing until the last possible moment.

"I think it was all about trying to be three steps ahead of the audience and creating that sort of intricate architecture as well as doing a character that puts on a mask up on a mask upon a mask," he says. "Just sort of navigating through all of that is emotionally fulfilling as well. I think you feel for these people because it is not a situation of black-and-white, good-versus-evil; there is that gray area and everybody is a human being in the film."

Perfect Stranger is directed by James Foley; and it is the rare film set in New York City that was also filmed there with locations that include "ground zero" - the site of the former World Trade Center towers.