Watch out for ... Jennifer Garner

One's natural instinct (as honed by Hollywood schadenfreude) is to hate on Jennifer Garner for seeming to have it all so together – career, marriage, motherhood, etc. – except that she's so darn nice about it.

After the television spy series "Alias" shot her to stardom, a role for which she won a Golden Globe and a SAG award, she has appeared in films such as "13 Going on 30," "Elektra" and, more recently, "The Kingdom."

While Garner, 35, may have a reputation as something of an action babe, in "Juno" she plays a high-strung yuppie who desperately wants a baby to complete her vision of lifestyle perfection, so she and her husband (Jason Bateman) arrange to adopt the baby of pregnant teenager Juno (Ellen Page).

The role could easily slip into sour caricature, but Garner – supported by director Jason Reitman and screenwriter Diablo Cody – finds the inner warmth needed to melt the chilly exterior. She allows the character to undergo an unlikely transformation, a seemingly literal change of heart.

Garner, who is appearing through early January as Roxanne in a Broadway production of "Cyrano De Bergerac," was whisked into Los Angeles on a recent Monday (when most theaters are dark) for less than 24 hours to do press (including this interview), attend a red-carpet premiere of "Juno," then catch a red-eye back to New York.

As if that schedule doesn't seem strange enough, "I'm not even going by my house actually," she said, "which is even weirder."

One of the things I found interesting about your character Vanessa in "Juno" is that, at times, she seems like the heavy, if not exactly the villain. Then there's a turn which makes her more sympathetic. Was seeding that transition something you had to keep in mind?

I don't think that I was consciously thinking, "Now she's changing." To me, it was much more about this woman who has probably been a perfectionist her whole life and that's how she's gotten to yuppie status, something I'm sure she's very proud of.

But the problem is, even if you give having a baby 110%, it's not something you're in control of. Even if you give your relationship 100% and you do everything just right, there's another part of the equation you are not in control of. And I think what was fun to me was playing somebody who is trying to keep her life together by controlling the little tiny things, and it's unraveling, and in the unraveling her heart opens up in a way that it probably hasn't since she was a kid.

Some women seem like they wouldn't be very good mothers, and then they have a baby and they are totally dedicated to it, while some women never seem to really fit into the role of motherhood.

I don't think you can know what mothering is going to do to you as a person until you're there. Personally, I would have thought that I love my job so much, I would have thought I would be working straight through and it wouldn't affect me. Or that I would just leave the kid with my mom and go on vacation for a week with my husband. I pictured myself as very much "I have my own life, I do my own thing," and that hasn't been the case whatsoever. So I think you can't know until you're there.

It's also interesting how when people are expecting, they know their life is going to completely change but don't know exactly how.

And everybody in the movie is going through that. Everyone is growing up in their own way. It's a coming-of-age story for about five different characters.

One of the remarkable things about "Juno" is that so many of the secondary characters, which could pretty easily be underwritten, are really given full consideration, they're fully drawn. Was that something you noticed when you first read the script?

I did recognize it when I was first reading it, because it was a surprise to read a script where all the smaller characters were so finely drawn and had so much going on. Often the smaller roles are kind of stock roles, so you don't spend a lot of time with them.