Beyonce in a Candid Exchange on 'Dreamgirls'

Thousands of teenagers were screaming, wailing for a beautiful, young woman -- a global pop star far from home who was spending a very special night backstage practicing her Japanese.

The beautiful, young woman is Beyonce Knowles, on tour in Tokyo.

On this night in September, she turned 25. That she chose to celebrate this day far from friends, family and home is just part of being Beyonce, we learned.

"I'm just now starting to get it -- balance," Knowles said. "I'm starting to learn to take care of myself, and usually, it's all or nothing. I work really, really hard, long hours, or I do absolutely nothing."

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And over the last few months of watching her behind the scenes, from Tokyo to Chicago, we never saw Knowles doing nothing.

We saw a major contender for the hardest-working woman in entertainment who endured grueling 15-hour days, a work ethic based on unrelenting pace.

"I was really exhausted when I was in Japan," she said.

But exhaustion is no excuse for Knowles.

"I know when people are in the audience they come to see -- they want to see -- a show. They want to live out their fantasies," Knowles said. "And I see when I am looking in the audience it doesn't matter how sad or how weak or whatever emotion they feel. For that two hours they think they are me. So they don't want to see something boring, so I give them a show."

Knowles is enjoying her success, but there is no doubt that she feels the weight of extraordinary pressures that are placed upon her and that she places on herself.

"Sometimes I feel like, because I give so much, people expect so much," she said. "And it doesn't matter if I hit the highest note for 10 minutes. People expect that."

The former lead singer of Destiny's Child has been in the spotlight since she was a teenager and has had to overcome ever more demanding obstacles. But Knowles says she relishes the challenge.

"I'm only 25, but I was 16 when we [Destiny's Child] had our first No. 1 single. So I've already had a 10-year career, and I still I haven't seen the best of myself, not in movies or in music," Knowles said. "I'm still growing, so that's really exciting when I think about that."

On the simplest level, Knowles quickly draws a crowd, and she can't help but notice the effect she has on people. But the once-shy little girl from Houston still finds the adulation stunning.

Folks weren't screaming when Knowles showed up at the Chicago Art Institute, but she sure created a stir.

The notoriously private and protected star sat down for an extended and candid talk.

The Alter Ego

Knowles says she created an alter ego named Sasha when she was a child to help her overcome her fears on stage.

"Sasha is so confident and is fearless and can do a lot of things that I can't do. She protects me," she said.

But Knowles had to leave Sasha at home to snag her latest movie role: the Diana Ross-inspired role of Deena in "Dreamgirls," which will open in theaters next month.

"I wanted to play Deena more than any character ever in a movie," Knowles said. "I have done a couple movies, and I have wanted to be a part of them but never even close to the passion that I felt for this character."

There was just one problem. Sasha, the alter ego Knowles relies on to perform, is confident and fearless; Deena, the character Knowles plays in "Dreamgirls" in the movie, was not.

"Initially the directors saw my rehearsal with Destiny's Child, and I was the over [the] top strong belting Sasha, and they were, I think, a little shocked. 'Well, maybe she … maybe she isn't Deena,'" Knowles said.

"They were concerned that young Deena -- who was very shy and naive -- they were afraid that people wouldn't be able to look at me as that character."

Nevertheless, Knowles got the part. And you see the transformation on film -- bold Beyonce becomes meek Deena.

"When I watch the movie, I don't see myself at all," Knowles said. "There are certain moments when I watch the movie and I'm so upset. … At one point that I had to look at my mom, and say, 'Oh I can't stand Deena.' Like it wasn't me. But that's how I know I did my job."

That very weakness and timidity, however, provide a point of contrast for the transformation that Deena finally undergoes.

"By the end, I have my strength. By the end, I find my voice," Knowles said. "And it's because she is so passive and she completely has no opinions, when she finally does it's so effective and so powerful."

Becoming Deena

This struggle between competing emotions provided fodder for Knowles' new CD, "B'Day," which she said she recorded over just a couple of weeks, jumping between three recording studios within days of finishing "Dreamgirls."

"I am not sure how actors release a character if they don't have an album or music. I guess they just go and make another movie and get into another role," Knowles said.

"I used making this record as a vehicle to find myself again, so I let out a lot of emotions that Deena was feeling that I wasn't, and I am so happy because I feel like I was able to connect with people that are going through certain things that I am not."

Some of Deena's emotions seem pretty darn angry. Knowles herself may not be angry, but she is restless, and also disciplined.

To capture the look she wanted for "Dreamgirls," she shed 20 pounds.

"Diana Ross was my inspiration as far as the look, and she was a lot thinner, and I wanted to have that look so I went for it," Knowles said. "No one asked me to do that. That's just something that I thought would be good for the character."

To slim down, Beyonce kept herself to a "cleanse" diet that involved no solid food, just cayenne pepper, maple syrup, water and lemon.

"It was very spicy, and I was grouchy and hungry for a long time," Knowles said. "It was difficult. I'm a Southern girl. I grew up with huge portions of food, with candied yams and macaroni and cheese. Everything fried."

A Girl With Big Dreams

Knowles is now back to what she calls "Beyonce" weight. And now that she believes in herself as an actress, she has characteristically big goals.

"I want to be the first African-American woman to have a Tony, an Oscar and Grammys," Knowles said.

But she is modest about "Dreamgirls."

Knowles admits this may not be the role that snags her a golden statue, though she hopes it will prove to her detractors that she is a serious actress.

Oscar or no, Knowles confesses the role may well become part of her legacy.

She admits it has crossed her mind that someday another young actress might play the 25-year-old diva at the height of her talent and celebrity.

"When I think about Diana Ross playing Billie Holiday and now I'm playing someone loosely based off of Diana Ross, maybe in 25 years, someone will be playing me," Knowles said. "And that's so amazing and beautiful.

"Everything I do is honest, it's real," she said. "I am very much in control of everything I do, and I feel like everything I do is a part of my legacy. So I try to make sure that it's something that I'll be proud of 20 years from now."

And yet, Knowles says the hardest part of being Beyonce is just that -- living up to the legacy, to all those enormous expectations.

"Every single time I do something I'm trying to top myself," Knowles said. "But I feel like I was born for this, and actually I know I was born for this."

One senses Knowles is still looking to make an even larger mark, a mission often lost in the media frenzy that often surrounds the star.

On the topic of her much-rumored romance with hip-hop mogul Shawn "Jay-Z" Carter, she politely demurs.

"It's so crazy that in the same tabloid we're broken up and we're married. At the same time. But that's a part of the tabloid so, it's part of my job," Knowles said.

"Thank God it's not anything that's too harmful, you know? It's not anything that's too serious that I lose sleep over."

Despite the exhausting schedule, the relentless attention, and the pressures of history on her shoulders, Knowles exudes a surprising calm.

"I feel like I'm balanced -- I have a life," she said, pausing to reconsider. "Well, I'm working on that."

She reconsiders once more.

"But I don't feel like being a celebrity defines me," she said. "And I feel like right now, if I wanted to stop, I could be completely happy."