"She's not that tall, but you can tell she's strong," says Jessica Biel, talking about her 55-pound pit bull mix — but she could just as well be talking about herself. Biel and I are discussing our love for our dogs (she sleeps with hers as I do with mine) as we wait for her new best friend, Jennifer Garner, to join us for dinner at Madeo, a legendary Italian restaurant in Beverly Hills where Al Pacino is said to keep a standing reservation. The hostess has seated us in a booth in the farthest corner from the door in an attempt to offer some privacy, but Biel's beauty can't go unnoticed. Fresh from a taping of The Tonight Show with Conan O'Brien, Biel has her hair perfectly styled, her makeup perfectly applied. There are sequins sparkling on the T-shirt under her open cardigan sweater. And just moments ago, the whole restaurant watched as she gracefully strode toward this back booth.

Underneath the glitter and gloss, Biel is the real thing. At 27, she has been able to figure out how to take life seriously without taking herself so. I become aware of this when we continue our bonding over the climb she has planned up Mount Kilimanjaro. (I climbed the same mountain a few years back.) One of a group of environmental activists and artistic types who have named their trek Summit on the Summit, Biel is climbing the mountain to call attention to the world's clean-water problem. More children, she informs me, die from polluted drinking water than from AIDS and malaria combined — one child every 15 seconds.

A murmur sweeps through the room, a sound not unlike the low roll of wind along the high heathered regions of Mount Kilimanjaro, as a slightly harried Jennifer Garner rushes through the restaurant and slips into our booth.

"Sorry I'm late, but I got lost and—" Garner stops herself upon seeing the gussied-up Biel. "You look gorgeous!" she exclaims. "And look at me. I didn't even change my clothes to come here," she says in the exhausted-but-happily-so tone of a mother with two young children. Garner, 37, is dressed in a black cotton turtleneck and black jeans. She wears no makeup at all, and her hair is pulled back in a ponytail. She possesses an incongruous combination of sexual charisma and girl-next-door normalcy. There is no artifice about her — it is the essence of her appeal. She is Sandra Dee—nuded.

The two stars became fast friends on the set of the film Valentine's Day, a kind of American version of Love Actually with a roster of stars that includes Julia Roberts, Anne Hathaway, Patrick Dempsey, Bradley Cooper, Ashton Kutcher, Jamie Foxx, Jessica Alba, and Shirley MacLaine. Biel plays a single sports publicist who hates the holiday; Garner's character has an affair with an obstetrician played by Dempsey and discovers late in the movie that he's not what he appears to be.

"We don't work with a lot of women on our films," says Garner, explaining why she and Biel connected during the shoot. "And I haven't worked much at all lately, to tell you the truth. The two weeks I worked on this movie were the only two weeks I've worked in about a year-and-a-half because of being pregnant and now having a 1-year-old. But when I do work, it's always one woman and a bunch of men in my casts — maybe my character has a friend in the script, but not always. It's odd. So on this film, it was great to have someone like Jessica around, even though most of our scenes as best friends were over the phone."

"And do you find this true, Jennifer?" Biel asks. "I know I do: You never really bond with all the guys in your cast like they do with each other." Biel is nevertheless excited to tell Garner about her work "shooting N4 machine guns and 9-millimeter Berettas" on the A-Team movie she's making with Cooper, Liam Neeson, and Patrick Wilson.

The waiter approaches our table. "I'd like some wine," says Garner. "I never go out much anymore, so I'm going to have a glass of wine. This is living it up to me now." The women each order an appetizer, a main course, and an order of pasta Bolognese to be shared by the three of us.

"Oh, I heard the sweetest story about Violet the other day," says Biel, mentioning Garner's 4-year-old daughter (older sister of 1-year-old Seraphina). "One of Violet's classmates came up to her and said, 'I heard Jennifer Garner lives in your house.' And Violet said, 'No, she doesn't.' The other kid kept insisting, so Violet came home and asked you, 'Mom, who is Jennifer Garner and why are people saying she lives with us?'"

PHOTO GALLERY: See pics from Jen and Jessica's photo shoot here.

Garner downs almost half her glass of wine at hearing the story. "Wow. That's true," she says, then pauses, considering whether to give more credence to it. "She just knows me as Mom, so I did have to explain to her for the first time about the difference." She takes another sip. "I'm just holding down the fort while Ben works right now," she says, mentioning her famous husband, Ben Affleck, who has 10 more days of filming The Town, a movie he wrote, is directing, and stars in. "I'm so impressed by his discipline. He gets up and works out every day at 4 a.m. before heading off to work. Every day. I used to do that sometimes for Alias," Garner says of the television show that made her a star (and won her a Golden Globe for Best Actress in a Drama Series as well as a SAG Award and four Emmy nominations). "But not every day. And I'd do it for 30 minutes, maybe 45. He does it for an hour-and-a-half. He comes home and collapses, and then rewrites scenes for the next day, then crashes and does it all over again. He's worn out. Jon Hamm is in it, too. It's kind of a heist movie, and Hamm plays the FBI guy."

"Mmmm ... Don Draper," says Biel, invoking the name of Hamm's character on Mad Men. "I'm fascinated by Don Draper. But I hate him."

"Like every other woman, do you want to sleep with him?" I ask.

"No!" she says emphatically. "No, I don't. Not at all."

Garner giggles and orders another glass of wine.

"Both of you have very famous men whom you really do sleep with," I venture. They are reluctant to talk about their famous significant others (Biel has been dating Justin Timberlake since 2007, and Garner married Affleck in 2005), but I have to ask. "Does that double your own fame? Does it become part of your girl talk?"

"Well, we don't need them to be famous ourselves," says Garner. "It's not like I go to Jessica, 'Oh, how's your famous boyfriend?'"

"But come on," I prod. "You have to be aware you have really cool partners."

"Yeah, from time to time we talk about swapping," Garner deadpans.

It's Biel's turn to giggle now, but then she turns serious. "It does help to have a partner who understands what fame is about and can share that with you. It's a hurdle you don't have to get over."

And how do the women cope with fame? "I think I have it all in perspective," says Garner. "If you're healthy and happy and you have a roof over your head, then that's what's important."

Read the rest of the interview in our March 2010 issue, on newsstands February 9th.

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