"The Sisterhood of the Traveling Pants" opens today. It's the story of four very different teenage girls -- with very different body sizes -- who find that one pair of used jeans magically fits them all. The pants are also tried on by another character, Bailey, played by 12-year-old Jenna Boyd. Though the jeans don't fit Bailey -- the pants have only so much magic -- the role of a young girl with a big problem is perfectly suited to Jenna.

Jenna has been involved with acting since she was discovered in a modeling search at age 2. She already has been in a wide range of roles: She appeared in a few episodes of "Barney." ("All I remember is, I would say, 'It's time for Barney Says.'. . . It's really embarrassing.") She has also been in some movies meant for grown-ups.

KidsPost's Scott Moore spoke with Jenna about how she learned to cry on cue for her "Traveling Pants" role, her figure skating goals and her actor-brother, Cayden, who has a role in "The Adventures of Sharkboy & Lavagirl in 3-D."

The character Bailey is very open, self-assured, talkative and seems more mature than her age. How does that compare with you?

A lot of people say I am very mature for my age. But I'm not the kind of person to go up to someone and automatically make friends, the way Bailey is.

Have you read Ann Brashares' book that the movie was based on?

I've read all three [in the Sisterhood series]. I love them all a lot. I read the first one when I found out I was going to play Bailey. I finished the third a month and a half ago.

How did you prepare yourself for the crying scene?

I have to focus the whole day. I can't talk to anyone. I have to focus about being sad. I have to understand what [the character] is going through. That will make me cry and feel what they are feeling. [Bailey] is just so afraid of not getting to know people. I sort of thought, I have my little dog and my mom, and I imagined looking at my dog for the last time.

With you and Cayden having movies coming out in June, is there a friendly sibling rivalry in how well the movies do?

Everybody says we have kind of a rivalry; we really don't. We're really supportive of each other. We've never worried about how the movies have done at the box office.

Have you ever worked on the same movie or TV show?

No. We want to. It's pretty difficult when the family is split up everywhere. . . . It would be cool to play a brother and sister that fight. We can do that.

[Maybe brother-sister fighting wouldn't be acting at all. Cayden, 11, later shared with us that Jenna's movie is "definitely a chick flick." And, "Since she is older than me and has a little more experience, she thinks she knows everything. . . . No, she doesn't."]

Tell me about your figure skating.

I get up at 5 in the morning and skate for about an hour and a half, five days a week. I haven't competed a lot [but] I'm getting into the higher levels of skating. I'm doing some double jumps and maybe in a year or two I'll start doing triples. . . .

I've been skating as long as I've been acting, about nine years. I love it.

What's your goal?

I think it would be cool to win an Academy Award and an Olympic medal.

You acted in R-rated movies "The Missing" and "The Hunted." Have you watched them?

When I was in "The Missing," I took a bunch of my friends to see it. They had their feet up and were crying.

Have you watched any other R-rated movies?

No! Mom won't let me.

Amber Tamblyn and Jenna Boyd in "The Sisterhood of the Traveling Pants."