WASHINGTON — Russell Crowe trusts his instincts, and right now he's almost certain they are dead-on. He just needs confirmation. So he darts his piercing eyes toward me.

Five days earlier I was in the Washington Post newsroom, editing articles for the Metro section. Now I'm in Crowe's Beverly Hills hotel suite, along with director Kevin Macdonald and actresses Helen Mirren and Rachel McAdams. Three Academy Award winners. A magnetic young star. And a newspaper guy you've never heard of, still wondering how he got here.

We're dissecting the script for "State of Play," a big-screen thriller that revolves around the friendship-rivalry between a politician and a reporter. It's Jan. 6, 2008, the eve of three months of filming.

Crowe's voice booms across the room. Surely, he asserts, a journalist who's been given photos that break open a sensational crime story would never jeopardize the scoop by sharing them with the police. Right?

I've known him less than 48 hours. Not long enough to gauge whether he finds me useful — or a pest. Certainly not long enough to calculate whether the answer I'm about to give will earn me an icy glare or a nod of respect.

My new, surreal role as a pampered movie consultant is quite agreeable: hanging out with A-list celebrities, traveling first-class, staying near the beach in Santa Monica, fattening up on catered meals. It would be nice to stick around.

It also would be nice to leave with some integrity intact.

"In most situations, you're right," I begin, making eye contact while building the courage to drop a big "however" on Crowe, who plays the reporter. He's our meal ticket, the guy who rescued the movie six weeks earlier after Brad Pitt abruptly dropped out amid the Hollywood writers' strike. If he gives the word, I'm probably on the red-eye back to Washington.

After explaining why reporters often have adversarial relations with police and protect confidential documents at all costs, I outline a very narrow window of exception. If lives are in peril, then your duties as a citizen trump your principles as a journalist.

Crowe pivots toward Macdonald, who had cautioned me that his leading man doesn't necessarily see the noble side of my profession. I brace for the worst. Instead, an articulate ally emerges.

The exchange we just had, he tells Macdonald, needs to find its way into the scene.

"That was fun, man," Crowe says to me later, after we spar a few more rounds over the script.

My fun would stretch from Los Angeles back to Washington, where most of the exteriors were filmed. And before the cinematic circus left me behind, I would end up with a two-line role in the movie opposite Mirren, who'd make me laugh and blush by whispering a slightly risque congratulation (it had to do with losing my acting virginity).

I'd become a card-carrying member of the Screen Actors Guild; take home a personalized director's chair; accompany McAdams to a play and get swarmed by her adoring teenage fans during intermission; and fly on a private jet with producer Andrew Hauptman, who became a good friend, to watch the professional soccer team he owns play a home game in Chicago.

Oh, and I'd get man-hugged by Crowe.

Like most of life's craziest adventures, this one came out of nowhere.

On a lazy Friday in June 2007, Len Downie, then our executive editor, asked whether I was free to have lunch with Macdonald, an Oscar-winning documentary filmmaker ("One Day in September") fresh off the success of his first feature, "The Last King of Scotland."

I hardly had the resume to dazzle Hollywood. After working for two decades as a news reporter and editor on both coasts, I joined The Post in 2002 as an assistant Maryland editor and worked my way up to Metro editor. But perhaps Macdonald saw in my eyes that his project married two of my lifelong passions, journalism and movies. Because within a few months I was his guide, even touring him and Pitt around our newsroom one afternoon.

As I did this, two themes came into sharper focus — both worrisome.

One, celebrities who are hounded by the paparazzi see many, but not all, of the differences between daily newspapers and supermarket tabloids. Two, while Macdonald was determined to put his distinctive imprint on "State of Play," the movie was being adapted with some degree of fidelity from a popular London-set BBC miniseries of the same name that, though rollicking fun, is an ethical nightmare by American standards.

Its ace reporter pays sources for information (an absolute no-no in the United States), surreptitiously videotapes a source in a hotel room (a firing offense, and a felony in several states) and generally behaves like a walking conflict of interest (and in a bedroom scene with the politician's wife, he does more than walk).

Macdonald and his team — art directors, costume specialists, property masters, and on and on — worked tirelessly and spared no expense to capture authenticity on the micro level.

They had me e-mail photos of the clothes and shoes that reporters wear. They needed to know what brands of pens we favor. They found binders like those we use to store old newspapers and then stained the covers with dirt and coffee to age them appropriately.

They arranged for me to lead a "boot camp" for scores of extras, coaching the background actors on how to pantomime phone interviews and type on their computers. How's that for action-packed drama?

Mirren asked me for a list of newspaper terms, which she jotted on a legal pad and drew from to sprinkle into her dialogue. (A front-page article became "an A-1 story.")

Mirren plays the Washington Globe's British expat editor, and Crowe is its shambolic, streetwise reporter whose actions alternately impress and repulse the upstart blogger portrayed by McAdams.

When it was finished, the massive Globe newsroom, built on a Culver City soundstage and decorated in painstaking detail, was so realistic that you could have put out a paper if the computers really worked.

But on the macro level, my crusade for authenticity bumped into unyielding walls at times. When I repeatedly objected to the illicit-videotaping scene, Macdonald politely made clear that in the end, plot rules.

My experiences with Crowe turned out to be positive. Sure, I think he's deeply suspicious of reporters in his own life. But he put aside preconceptions for the most part and used his formidable talents to submerge into my world.

I'm not a trained critic, but in the end, I'm proud of the film.