If Kiss Kiss, Bang Bang turns fun-lovin' Iowa actress Michelle Monaghan into a movie star -- and it probably will -- she will thank filmmaker Shane Black and her two bad boy co-stars for the opportunity.

"One of the things I like," Monaghan says as she tracks Kiss Kiss from Cannes to the Toronto film festival and now into theatres, "is that Shane really took a chance."

Kiss Kiss, Bang Bang is his risky directorial debut after a solid career as a screenwriter.

The movie is also her first lead role after a handful of support characters in movies such as Unfaithful, It Runs In The Family and The Bourne Supremacy. As recently as this year's Constantine, she cringed as all her scenes were cut out of the Keanu Reeves supernatural thriller.

"He could have very easily chosen someone else who had a lot more experience," Monaghan says of Black.

But Black, producer Joel Silver and co-stars Val Kilmer and Robert Downey Jr. all knew it was going to be Monaghan as soon as the 29-year-old native of Winthrop, Iowa, walked out of the audition room.

"It was obvious when she left the office that no one else was going to get this part," Kilmer tells the Sun. "And there were some great actresses up for it."

Says Silver: "We looked at a lot of girls and Michelle came in and we hired her. It was very A to B to C. It was very simple."

This was two days before shooting on location in Los Angeles. "For two days, I was literally just freaking out," Monaghan remembers.

Then she worked with her two goofy co-stars, who had already struck up a warm friendship.

"At the end of my first day," she says, "I went: 'Oh my gawd! I was just totally accepted.' It was the coolest thing."

Then the fun and games started in earnest -- but always on set, never in a party mode off-set, she says.

"We didn't really see each other off the set because we were working all night and sleeping all day. So I really only saw them on set. We were always joking.

"Certainly, the dialogue and all the characters lent themselves to the madness. We were all just having a ball and it was all at night so we were just a bunch of vampires. It was awesome! It was really so much fun."