ONE HECKUVA MOTHER DIANE KEATON KNOWS BEST, SAY ON-SCREEN DAUGHTERS IN `BECAUSE I SAID SO'.

Byline: Evan Henerson Staff Writer

Her character in the romantic comedy ``Because I Said So'' is an exasperating busybody who meddles outrageously in her adult daughters' lives. But on the film's set, Diane Keaton was part den mother, part mentor and -- face it -- part royalty.

Mandy Moore and Lauren Graham signed on to play Keaton's daughters in the Michael Lehmann film -- opening Friday -- largely for the opportunity to work with Keaton. Mission accomplished, and now both actresses are about ready to form the latest branch of the Diane Keaton Appreciation Society.

``She thought I was funny. She said, `You should have a lot of confidence and faith in yourself,' '' Graham recalls. ``She said I should write a book, mainly because I didn't shut up. The fact she said things to me made it true because it was coming from somebody I like.''

For Moore, undertaking her first adult romantic comedy role, Keaton chimed in to help ensure that the younger actress was satisfied with her own work. As Lehmann and the crew were about to wrap one scene and move on to another, Keaton would see Moore looking unsatisfied and would ask director Lehmann to shoot an additional take.

``Diane kind of helped me come into my own a little bit,'' Moore says. ``She's her own entity, and she's totally under control.''

`One of the girls'

Keaton herself, however, brushes adulation aside.

``I'm just a working woman,'' says Keaton. ``Show me a script, and, if I'm available, I'll do it. Frankly, I'm lucky to be working at all.''

``Diane is one of the girls,'' says Graham. ``She doesn't like when there's any kind of, like, `Miss Keaton.' She's like, `Ugh, God, no!' She wants to be one of us, and she doesn't like the feeling that there's some kind of preciousness regarding her.''

Girl-girl bonding figured to be easy while concocting an estrogen-fest like ``Because I Said So.'' The movie is directed by a man and contains a love triangle, but with the comic push-pull of moms and daughters at issue, nobody should expect ``Because I Said So'' to be double billed with ``Gridiron Gang.''

Imagine James Brooks' weepie ``Terms of Endearment'' as a romantic comedy where the interfering mom character has morphed into a sex-starved klutz who frequently ends up with a faceful of elaborately prepared cake.

Meddling mom

Convinced her daughter Milly (Moore) makes only the wrong choices where it comes to men, Daphne Wilder (Keaton's character) takes matters into her own hands. She places an ad on an Internet dating service for her daughter -- and personally interviews each candidate.

Milly has two older sisters (Graham and Piper Perabo) who are, if not the apples of their mom's eye, certainly the peach and plum. All four women shop together, take massages together and conference-call one another via cell phone at every opportunity -- including during sexual encounters.

The unhitched Milly, of course, gets the brunt of daffy Daphne's lunacy. At one point, a laryngitis-stricken Daphne is stuck on her daughter's couch scribbling notes asking Milly to explain ... er ... an experience a parent doesn't typically ask her child to explain.

Ah, problems between moms and daughters -- who among us can't relate?

Real moms and daughters

Keaton certainly can. Sort of. Her daughter, Dexter, is 11. ``She's already a tween,'' Keaton laments -- leaving Keaton plenty of time to meddle, if that's the way she elects to go.

``I don't think I'm the same kind of overbearing mother (as Daphne),'' Keaton says. ``I am probably an overbearing mother. The method of my being overbearing is more hidden maybe, but it's just as intense.''

Graham was raised primarily by her father. She's not a mother, but for seven seasons on ``Gilmore Girls,'' she has played one. Lorelai Gilmore's scenes with TV daughter Alexis Bledel are great fun to play, Graham says, as are those with Kelly Bishop, who plays her character's mother, Emily.

``When you're in your mother's house, you feel like a daughter, and then when you're in your own house, you feel you have to act like a mother,'' Graham says. ``There's always an imbalance. You're always getting told what to do too much, or you're getting too much friendship and not enough guidance.''

Moore says she experienced an inevitable and necessary distancing from her mom, Stacy, as her career advanced. Because she started her singing career young, Moore traveled with her parents. At a time when she might have been rebelling, Moore and her parents were instead growing closer.

``I think the past few years I sort of had to find my distance and find out who I was and find my footing as well,'' says Moore, 22. ``I think that was hard for my mother. Mothers see a lot of themselves in their daughters and vice versa. So that makes it beautiful, and it makes it really sort of messy as well.''

Dad ... and director

Lehmann, meanwhile, isn't entirely on the outside looking in. He has a daughter, a wife and a keen sense of observation.

``My wife and my daughter ... it's really interesting to see how emotionally charged that relationship is,'' Lehmann says. ``My relationship with my daughter can be emotionally charged, but it doesn't have the intensity that she and my wife have with each other. When they fight and when they butt heads, but also when they connect on something, it's pretty interesting to see.''

Father-son entanglements are regular cinematic fodder. Less so for mother-daughter tales, Lehmann says.

``I didn't really know there was that much material in popular culture that dealt with it,'' he says. ``So that made it really interesting.''

Evan Henerson, [phone]

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CAPTION(S):

3 photos

Photo:

(1 -- cover -- color) Maternal

Diane Keaton meddles better than anyone in `Because I Said So' Affairs

(2) Mandy Moore, left, Lauren Graham, Diane Keaton and Piper Perabo are a very close mother and three daughters in ``Because I Said So.''

(3) - Mandy Moore