HER BLUE PERIOD REBECCA ROMIJN-STAMOS PROJECTS A CERTAIN MYSTIQUE IN 'X2'.

Byline: Bob Strauss Film Writer

Rebecca Romijn-Stamos may be mighty blue these days. But that doesn't mean she's unhappy. If you were getting away with behaving as badly as she's been lately, you'd be having a good time, too.

Not that she's really doing anything nasty. Happily married for half a decade to fellow actor John Stamos, the statuesque former supermodel's

ideas of fun are hiking in the hills with her dogs and checking out flea markets and open houses with her sister.

But Romijn-Stamos has gotten very, very adept at enjoying life's darker pleasures in the fantasy realm of the big screen. Last year, she did just about everything wrong a gal could possibly do - and received her first big collection of movie critic raves - in Brian De Palma's ever-so-aptly titled ``Femme Fatale.''

And now Romijn-Stamos is getting the lioness' share of credit for being the most amusing thing in the massively complicated, character-packed ``X2: X-Men United,'' which opened in the No. 1 spot at the box office, grossing $85.6 million its first weekend in release. In the second film based on the Marvel Comics superheroes megaseries, Romijn-Stamos reprises her role as the villainous, blue-skinned shape-shifter Mystique. And unlike in the first film, she has more than one line - and many, many more evil, sexy, funny and even sympathetic moves than she got to strut the previous time out.

And she still appears naked as a blue jay while doing it.

``I've been very, very careful, especially about what I've said no to,'' the 5-foot-11, athletic blond 30-year-old says of managing her budding film career. ``I encounter the boring, pretty-girl roles all the time, and that's not that interesting to me. I've really been looking for the ones that are a little more flawed and have a little more damage, the ones that are broken. I think it's really just as important what you say no to as what you say yes to.''

It's not a perfect science: Witness Romijn-Stamos' participation in last year's universally derided remake of the sci-fi thriller ``Rollerball.'' But given well-written characters - with as few inhibitions as possible - the actress has proven more than up to any challenge bad-boy screenwriters can invent.

Mutant anger management

While giving due credit for much of Mystique's ``X2'' charisma to others - when she's impersonating someone, obviously, a different actor is doing the work, and the blue makeup/costume's delicacy meant extensive use of stunt doubles - Romijn-Stamos was thrilled by the opportunity to explore so many extra emotional dimensions in a special-effects-driven fantasy blockbuster.

``My character's obviously angry - and she has her reasons for being angry,'' the actress notes. ``When (Alan Cumming's new mutant) Nightcrawler asks her, 'When you can look like anybody else, why don't you?' she answers, 'Why should I have to?' It just sums her up.

``But I was also happy to make her sort of a sexual predator this time, who would do 'em as fast as she'd fight 'em. So it was nice to develop the character.''

This resulted in one of the film's kinkier scenes. Mystique and her evil mutant boss Magneto (Ian McKellen) team up with the X-Men to stop a mutant-hater who wants to destroy them all. Attracted to good guy Wolverine (Hugh Jackman), she enters his tent looking like the X-Woman he longs for, Jean Grey (Famke Janssen), and tries to seduce him.

``The menage-a-five or something like that,'' is how Janssen, who like Romijn-Stamos is of Dutch heritage, describes the bizarre semi-coupling. ``Well, Hugh was just lying in the tent, and we were just climbing on top of him one after the other.''

Just another day at the office for the naked blue lady. But don't call her that to her face.

``I know, at the end, what the effect is, but there's really quite a bit of costume,'' Romijn-Stamos insists of Mystique's look. ``I mean, it's 150 prosthetics; I'd say probably 65 percent of my body is completely covered in sheets of silicone. It's not very thick, but I felt very covered up.''

But then she bursts into laughter.

``I've just been in complete denial about the nudity thing,'' the actress cracks. ``I'm like, 'I'm not naked. Seriously, I'm not. You guys - am I naked?' 'Yes Rebecca, you're naked. Just accept it.' ''

Not model behavior

As anyone who's seen her sometimes legendary talk-show appearances knows, Romijn-Stamos has a raunchy sense of humor and unpretentious manner that, besides making her perfectly approachable now, must have made her stand out in the haute haughty world of cover-girl modeling. Asked if she's met many other humorous models, she has an immediate comeback.

``You mean, who mean to be funny?'' she quips. ``Yeah, I don't know what that's all about. A lot of them are from other countries so, like, English is their second language. They don't mean to be funny, they just are.''

Seriously though, a good sense of humor was vital to surviving both ``X-Men'' shoots. Back to that blue paint/costume business: There really was a lot to it. Fortunately, on the sequel, Romijn-Stamos had another indigo-slathered cutup, Nightcrawler Cumming, to commiserate with.

``It was good in that Rebecca and I realized how important we were to each other - and that ended up canceling lots of the discomfort,'' the Scottish actor says.

``We had a little support group going for each other,'' Romijn-Stamos adds, ``Since we were the freaks among the freaks.''

``Yeah, even among the X-Men, we were the outcasts,'' Cumming continues. ``So it was nice to have someone else who understood, because the makeup thing and getting up that early was really grueling. I was four hours, and 'Becca was 5 1/2.''

And that was just before the shooting started.

Talk about exfoliating!

``Eventually, at the end of the day when I pull all the pieces off, you get the negative of where the paint is, and you can see what was really covered up,'' Romijn-Stamos says, making one last stab at the not-really-nude argument. ``It hurts, pulls off the top layer of my skin. And the skin that's painted blue ... I hate to be a whiner, because I feel like I did so much complaining on the first one, and it's such a cool thing to be a part of, and I'm not digging ditches - but it's rough. It takes an hour and a half to two hours to get it off. You have to break everything down with another chemical, which burns your skin if you leave it on for too long.

``But the worst part of it is having everybody in your space, like in your physical space, picking on you,'' she continues. ``Five people constantly touching you up, it's crazy-making.

Well, she wanted to be an actress. But not initially, any more than she dreamed of modeling, as a girl growing up in Berkeley. It was just a lark to make money during college, but Romijn quickly got plucked out of the San Francisco agency she approached and whisked off to Paris for three high-flying years.

Upon returning to New York, she met and fell in love with former ``Full House'' mainstay Stamos. A stint hosting MTV's ``House of Style'' and the desire to be closer to the actor in California eventually led to serious pursuit of the second career. The sitcoms ``Friends'' and ``Just Shoot Me'' picked up on her comedic ability, and movies soon followed.

From one actor to another

Stamos, of course, has been an invaluable adviser through all of this.

``More in the beginning than now, John was an amazing coach, just in terms of steps to take to go into a different direction with my career, 'cause I was sort of bored doing the modeling thing,'' she says. ``He's been really supportive and really encouraging.''

So, when are we gonna see the happy couple together on screen?

``Not gonna happen,'' Romijn-Stamos vows. ``We've already sworn that we would never do that. People know we're together, we're photographed together, and we're already sort of shoved down people's throats as a couple. We also have a very private private life, and we like to keep that sacred a little bit.

``And also, would you want to work with your wife 20 hours a day?'' she says with a laughs. ``I mean, it's better for everyone when you go off and do your own thing - and then you come back and just share your experiences rather than be together all day long.''

The next thing Romijn-Stamos will be doing is playing a grieving mother confronted with extraordinary decisions in the cloning thriller ``Godsend,'' opposite no less a talent than Robert De Niro.

``I just want to keep on looking for good material and working with great people,'' says the good-intentioned gal. ``So far, that's where I've learned the most - I've worked with some pretty incredible people, and I just sponge off them. I love that, just love it.''

CAPTION(S):

3 photos

Photo:

(1 -- cover -- color) In `X2' Rebecca Romijn-Stamos mutates once more into the feminine MYSTIQUE

Steve Granitz/WireImage.com

(2) no caption (Rebecca Romijn-Stamos as Mystique)

(3) - Rebecca Romijn-Stamos on working with her husband actor John Stamos

Chris Weeks/Associated Press