NEW YORK—Actress Bianca Astor, 22, was excited to be cast in the role of a woman who suffers from anorexia nervosa for a filmed public-service announcement Monday.

Astor at a recent casting call.

"I can't believe it!" Astor said upon receiving the call from her agent. "I honestly didn't think I was going to get the part. I'm pretty thin, but I didn't think I was eating-disorder thin. I guess I am!"

The spot for the National Association of Anorexia Nervosa and Associated Disorders is part of a campaign designed to raise the public's awareness of eating disorders. According to ANAD statistics, 1 in 100 adolescent girls suffers from anorexia.

"The cool thing is that I'll be helping to make a difference," Astor said. "Besides appearing in the TV ads, I'll also be on billboards and the sides of buses. Everyone in the country will see me as the super-skinny girl."

"This will look really good on my résumé," Astor added. "I tried to pick glossies that were flattering, but this will definitely help drive home the point that I can play thin."

Astor has struggled to get her acting career off the ground ever since she moved to New York four years ago. She has modeled sporadically and worked as an extra on several daytime soap operas, and also appeared in two commercials, portraying Smiling Woman #4 in a Gap ad and a fungicidal-cream user for Lamisil.

The anorexia spot marks her first starring role and the first to highlight her extreme boniness.

"I was really nervous when I went in for the audition," Astor said. "When I got to the waiting room, I thought, 'I'll never be able to compete with all these girls.' I was checking out their hips, and mine were definitely wider than a couple women's. But I guess that in the end, I was the one with the right combination of talent and physique."

Astor said she doesn't suffer from an eating disorder, but is lucky enough to have been born with a slight build.

"I've just always been thin, ever since junior high," Astor said. "I'm blessed with a fast metabolism. Plus, I work out at the gym for three hours a day. And I'm careful to watch what I eat. And I dye my hair because my agent said it makes my face look more defined."

Astor's agent, Allied Arts' Debra Fayhill, said she's proud of her 5'8", 101-pound client.

"I'm so excited for her," Fayhill said. "I called her up and told her that the producers thought she was perfect for the role of Gretchen, the wholesome 20-ish woman who's starving herself to death. I've never heard anyone scream so loud."

Continued Fayhill: "Not many actresses get a chance to have this sort of impact on young girls. Hopefully, she'll really make a big difference in girls' lives, and stick in casting agents' minds when they need a beautiful, hollow-eyed wraith."

Although few PSA actresses have gone on to great success, Fayhill said she is optimistic.

"Look at Rachael Leigh Cook," Fayhill said. "She starred in the 1998 'Frying Pan' anti-drug spot from Margeotes, Fertitta + Partners, and she went on to play skinny women in the movies. Bianca is on the same track."

Astor is already practicing her line for the role.

According to the script, her ad will open with a close-up on a "frail, emaciated hand." The hand will reach across a restaurant table toward a piece of bread. The camera will pull out to reveal Gretchen sitting in a restaurant with a friend. Gretchen will change her mind and drop the piece of bread. The friend will ask what's wrong, and Gretchen will say, "Nothing." The word will echo eerily as the scene fades out to reveal a grave.

"Emaciated," Astor said, smiling and examining her hand held at arm's length.

After she was selected for the role, Astor called her friends to celebrate with a night on the town.

"Bianca was all, 'Do you really think I'm thin enough to play an anorexic?'" friend Fiona Lin said. "All of us kept saying 'Yes, totally.' She shouldn't doubt herself. She looks fantastic. Out of all of us, she so has the most visible rib cage."

Not all of Astor's friends say she's thin enough for the part.

"Bianca's thinner than most of us, but she's not very proportional," friend and fellow actress Tia Rialto said. "Personally, I'd buy her as a bulimic, but never an anorexic. Have you seen the flab under that girl's arms? Ugh."