Diane Keaton doesn't do double-takes. She does triples and quadruples of her own uncanny devising. If acting were figure-skating, her head-tilted, arms-akimbo, wry-smiled look of sweet befuddlement would have been named the Keaton - or the Annie Hall - decades ago. But Keaton never replays those mannerisms. She comes up with original, organic stuff movie after movie, year after year.

Over the phone from her home in Los Angeles, she recalls how enjoyable it was playing a jailer's wife who falls for a prisoner - Mel Gibson! - in Gillian Armstrong's underrated 1984 Mrs. Soffel: "Mel Gibson was about to become the hugest movie star and he was drop-dead-killer-gorgeous. It was so much fun looking at him every day. I got all excited."

Keaton may be even sexier now. The tremble of her body can signal either quivering tension or total disarming collapse - that's what made her so attractive and hilarious in Nancy Meyers' Something's Gotta Give (2003).

In The Family Stone (opening Dec. 16), she exercises a different set of muscles. She brings a mother tiger's glare, pounce and fierce caress to the role of the matriarch of a large liberal family whose members are at odds with her straight-arrow eldest son, Everett (Dermot Mulroney), and his go-getting girlfriend, Meredith Morton (Sarah Jessica Parker).

It's an ensemble piece. Did her Oscar-nominated, Golden Globe-winning performance in Something's Gotta Give reopen any doors to her for starring roles? "Picture me the way I was at the end of The Godfather," she says, invoking the image of the door shutting Kay Corleone out of her husband Michael's life.

"No, that success didn't open any doors. I wanted to think it would, but I knew it wouldn't, in a way. Who's going to sit down and write the stories that I would be at the center of unless it's someone like Nancy Meyers, a person who has experienced and understood the things I experience and understand? The kind of thing I'm right for frequently involves slightly more complicated relationships and a lot of dialogue and a good writer-director."

What Keaton finds harder to fathom is why Paramount never pushed for a sequel to the hit farce she did with Goldie Hawn and Bette Midler, The First Wives Club. "We could do it now - it's so absurd."

A noted director herself (the 1995 comedy-drama, Unstrung Heroes, is a gem), Keaton says she worried about whether the relatively untried writer-director of The Family Stone, Thomas Bezucha (Big Eden), could handle the gang of actors needed to pull off this ensemble piece. But the presence of producer Michael London, who did Sideways, gave her confidence. And she thought to herself, "Don't be so precious about your goddamn career. It's a good script. And Tom, as luck would have it, turned out to be a clever, graceful director, resilient and seductive with the actors."

Keaton catches her breath and admits, "When I was younger I had these enormous vanities about what I expected from myself. I'm glad to have a comfortable and fascinating life, but now I see it for what it is, so I can be braver and more spontaneous and say to myself, 'Oh, screw, just go out there and do it.'"

What hooked her into The Family Stone was the character of Sybil Stone. "She's not an over-the-shoulder mom or a sweet mom or a mean mom. She's a progressive woman who made a choice and decided that her family would be her career and her passion and her celebration. She gave her whole life and energy and considerable brain to it. And though she's facing an illness, she's not an unstrung hero, she really is an unsung hero. This movie pays homage to all those moms who cherished and revitalized their families. Sybil Stone grapples with pain and fear, but is invigorated and kind of saved by her family. That's such a positive statement to have, especially at Christmastime."

Offering the slightest suggestion that it's surprising to see how beautifully she plays off Craig T. Nelson (TV's Coach), Sybil's husband, sets off a comical shriek, "How could you doubt him? He's my husband! Craig T. Nelson is a great actor - you can't be on a TV series and be funny and believable and hold it together week after week and not be a great actor. I knew he was a good choice as my husband. It's the most healthy, lovely marriage I've ever had in a movie. It may be the most healthy, lovely relationship I've ever had with a man."

All through the phone interview, Keaton fields queries from her 10-year-old daughter, Dexter ("Yes, you can have the drinkable yogurt") and almost-5-year-old son, Duke ("big kiss, honey, see you later").

A single mother raising two adopted children, Keaton enjoyed making The Family Stone partly because "The idea of family has changed so much in my lifetime." Sybil has mothered a diverse brood that includes a gay son, Thad (Tyrone Giordano), with an African-American life-partner (Brian White). "I'm glad we got to step up to the plate and say, 'This is what families are!' Everyone has some kind of mix like that in their family."

Keaton supports Sybil's rage at Parker's character, Meredith, expressing doubt that any couple would choose for a child to be homosexual. "Sybil is looking at Meredith and what Sybil is saying with that look is, 'Are you really going down that path about my gay son and his partner adopting a baby?' There's no motive behind it except a pure fierce protective passion.

"Being a mother," she says, "I can tell you there are instances in your life where you kind of understand how you could kill for those kids of yours: 'Watch out, pal, don't cross that line because those are my kids.' Sybil can be pretty outrageous, but I think she's right, and she doesn't have a lot of time. I'm completely on her side.

"Remember Father Knows Best? Maybe this is the choice of the new century: Mom Knows Best. Of course, this century has already been slightly disappointing, hasn't it?"

Keaton says that only her outspokenness connects her directly with Sybil. "I had a career and I came to motherhood late and am not married and have never had such a trusting relationship with a man - and trust is where the real power of love comes from."  

by Michael Sragow