“I feel like a big piece of furniture,” Ms. Streep groans, referring to the fact that she is six months pregnant with her fourth child, a cause for a 22-pound weight gain that has made her famous cheeks almost chubby and her eyes narrower than usual. Having just returned from a fitting for a Valentino gown for the Academy Awards – she’s been nominated for best actress for “Postcards From the Edge” – she suddenly struts across a hotel room, doing a sendup of the high-fashion runway models who left her feeling fat and “humiliated.” Deadpan, she wonders aloud if “they can find that much material” to cover her frame. Callipygian concerns aside, at the age of 41 Ms. Streep has made 18 movies in the last 14 years; this is her ninth Oscar nomination.

And at this stage in her seemingly charmed life, when she’s moved to Los Angeles and has three children in three different private schools and is redoing a house on the Westside and worrying about fabric samples, she’s careered off the beaten path of high drama, if temporarily, to cultivate her comedic connections.From penis envy to brain envy, from slurping noodles to flatulence jokes, from a weird afterlife in a corporate building to an after-afterlife on a bus, this is the wacky landscape of Meryl Streep’s latest film, “Defending Your Life, ” directed by and starring Albert Brooks, who wrote the screenplay. The film, opening Friday in New York, is not exactly Streepian terrain, of the highbrow variety. Then again, Ms. Streep seems to have fashioned her career on being unpredictable.

But never before has she played such a breezy role, the adolescent figment of one man’s imagination, especially when that man is the irrepressible Mr. Brooks: only he could dream up the comic scenario of finding the perfect woman, played by Ms. Streep, once he’s dead. And so is she. Together, they shuffle along in their silly white afterlife robes, or tupas, down the corridors of Judgment City.With “Defending Your Life,” she says, “We’re opening the door, God forbid, to Albert’s brain.” Ever since she finished “A Cry in the Dark” (1988), a movie she says gave her gray hairs, Ms. Streep has been drawn to lighter fare.

First, there was the farcical “She-Devil” (1989), in which she played a Barbie Doll opposite Roseanne Barr’s grotesque housewife, though she now views that movie, which received unenthusiastic reviews, as having turned out to be a hybrid, like a “wildebeest.”

Next came “Postcards From the Edge” and her arch performance as the acerbic, drugged-out actress seeking a rapprochement with her overbearing mother. It was during the making of that film that Ms. Streep was paid a poolside visit by Mr. Brooks, who paced for two hours and pitched her his nutty and sweet movie idea about what really happens when you die.

“He never let me read the script,” she says, eating hamentashen, a pastry brought by a visitor on the Jewish holiday of Purim. (Raised Presbyterian, Ms. Streep descends from Spanish Jews who immigrated to Holland; rather than sign their Jewish name, they drew a line, which is what Streep means in Dutch.)”Albert said, ‘I have to come over and tell it to you.’ And it was like, ‘Then I say . . . then you say . . .’ and I fell in love with the idea.”

She-Devil Or Snooty Person?

Ms. Streep is certainly no stranger to the realm of comedy. From a comic turn in Woody Allen’s “Manhattan” (1979), in which she played Mr. Allen’s bisexual wife, to tragic roles laced with humor, such as the hip, disaffected Karen Silkwood, or even the comic elements within the rigid Lindy Chamberlain in “A Cry in the Dark,” she revels in the underbelly of humor.

In person, she is at once self-effacing and proper, wearing an elegant, black kimonolike dress, diamond-drop earrings and suede pumps. “My daughters and I have a game called Snooty Person,” she says, now affecting a very proper British lady, “and we go out in high heels and we’re very snooty and we do vulgar things. It’s sort of a joke on myself, because a lot of comedy, I think, is vulgar. It’s all a matter of taste.”

And what, exactly, are the vulgarities that the snooty people engage in? “Oh, they’re unmentionable,” she says, laughing.Over the years, reviewers have branded Ms. Streep’s selection of dramatic material as humorless. The New Yorker critic Pauline Kael, who described Ms. Streep’s performance in “Postcards From the Edge” as that of “an android,” was chief among her detractors, issuing incantations like: “If only Streep would giggle more and suffer less.” Even admiring peers, like Cher and Diane Keaton, have in separate interviews described Ms. Streep as “an acting machine,” a compliment that also resonates with robotic implications.

Whether such observations put pressure on an actress of Ms. Streep’s caliber to toss off her mantle of earnestness by lightening her load is unclear. Yet Ms. Streep says that before “She-Devil,” she had been looking for “something light for years, but I just never thought anything that was around was funny.” Her friends suggest that in addition to enjoying the relief of not taking home the doppelgangers from work, Ms. Streep has turned to comedy for the challenge of it and maybe because, at her core, she’s a cutup. And besides, Ms. Streep’s heroes include the comic actresses Katharine Hepburn and Carole Lombard.

Says Carrie Fisher, who wrote “Postcards From the Edge”: “As a human being, she’s really funny. But you haven’t seen that in most of her work. Right now, I think, it’s about coming closer to home for her.”

Adds the comedienne Tracey Ullman: “I called her up to ask her if I should talk to you. And I asked her what I should say when you ask about her comedic talents. She said I should just pause and say, ‘What comedic talents?’ ”

A Connoisseur of Comic Women

What tickles Ms. Streep’s funny bone most these days is the work of the tough-chick comediennes. “I like the ones who aren’t afraid or so concerned with being girlish and attractive. Yeah, I like Sandra Bernhard and Roseanne Barr because of the tougher stance. I like that it doesn’t bow to being appealing and can still be funny.”

None of which could possibly explain Ms. Streep in “Defending Your Life,” in which she plays the quintessential “girl” role, passive and pretty and muted and wise – the straight woman to Mr. Brooks’s funny man. Ask about her contribution to the film and, looking somewhat embarrassed, she says it was “lighter than air.” Ask about her technique in playing Mr. Brooks’s dream girl, and she cracks, “It’s very important to have good hair.” Ask about the resonance of her character, and she says there was none.

“I know Albert feels he’s written a whole woman, a completely full-blown person,” she says. “I didn’t know how to break it to him, he’s really not done that. He’s written an idea of a woman. And I did my best to fill those silver slippers. “But it was also fun,” she adds. “I thought, ‘Ah, the hell with it. You’re dead. You can do whatever you want.’ ”

A Careerist with a Twist

During the course of this interview, Ms. Streep emotes countless heavy sighs, a sign of her distaste for sitting still with a journalist. Her ambivalence is palpable. She worries about projecting a “starlet” persona, but at the same time has chosen to meet in a suite that the movie studio reserved at the Hotel Bel-Air, a swank establishment with its swans, lush gardens and pink facade.”I just never figure out this stuff,” she says, referring to her film choices, “except in an interview, because I’m not an analytical person and I basically take jobs that appeal to me for whatever the skewed reason is that they appeal to me. I’m not in analysis, and nobody asks me these questions at home.

“I mean, at this moment in my life, most of my day is spent with some guy who wants to know where to put the second toilet upstairs. That’s what I’m thinking about. I’m not thinking about acting.”And yet, Ms. Streep is also a shrewd careerist who is as ambitious as any actor in Hollywood. When asked how she feels about Madonna getting the role of “Evita,” a part for which Ms. Streep studied for more than a year before negotiations fell apart, she replies: “I could rip her throat out. I can sing better than she can, if that counts for anything.”

The loss of that role, which she says was a “bitter disappointment,” resulted in her being without a job and deciding to do an American Express Card commercial with children from one of her daughters’ schools. “I don’t believe in the company,” she says. “But I have a card, so I felt like I could kill two birds with one stone because my daughter’s school was in financial trouble. They got an enormous contribution from American Express, and I gave them one. So, it was good.”For now, at least during the remainder of her pregnancy, Ms. Streep is doing off-camera work, narrating Phil Joanou’s American version of Michael Apted’s “7 Up,” a documentary that follows the lives of 7-year-olds, with sequels every seven years.

Though she says she would like to return to the theater one day, Ms. Streep claims to have developed a case of stage fright that has grown “way out of proportion,” because she feels “followed by the expectation of what I’ve done.” So she misses the feeling of an audience, the roar of approval. “And that is something I was conscious about in picking those comedies,” she says, ” ’cause I like hearing a crew laugh.” Is Meryl Streep funny?She’s deadly serious when discussing the question, and her awareness of how sober she is is endearing, if not actually funny. She launches into a thoughtful response about how being comical is part of a bigger package, a spectrum of feeling. Then, she says, “I think I’m funny – and overanxious – and lazy.”

This last part hardly seems possible. Meryl Streep, lazy person? “Oh, yeah. I ‘m very, very lazy. If there’s a choice, I’d rather not do it, you know what I mean?”Since “Defending Your Life” is about death, it seems appropriate to ask about her feelings about an afterlife.

“Oy,” she bellows, as if some large object has fallen on her head. “Oy, oy. I believe there’s some point where it all is clear. I mean, I’ve been with people who were dying,” she says (she lived and worked with the actor John Cazale, who died of bone cancer in 1978), “and seeing that moment and seeing peace come. I do believe that. But I don’t see it as a sort of corporate building, like Albert.” One minute she’s a crackup; the next, quite pensive. “The other day,” she says, “I thought, ‘Boy, I’m ready to do something that takes a pound of flesh again.’ ” So much for Meryl Streep’s craving for comedy.