Actress and musician Hilary Duff poses for a photograph in Burbank, Calif., on Friday, March 30, 2007.[AP]

There are actors who sing and singers who act, but throughout pop history few entertainers have successfully balanced those twin careers.

Neither could Hilary Duff, though not due to lack of effort. While her career as a pop diva skyrocketed — she released two platinum albums and a best-selling greatest-hits disc in just three years — the former Disney child star found her acting career stalling. Despite her considerable star wattage, Hollywood had difficulty seeing Duff beyond her past sugary sweet roles and good girl persona (no rehab or pantyless partying here).

"It always shocks me the lack of openness, the lack of imagination that some casting directors have," Duff, 19, says in her girlish voice, sitting in a back corner of one of her favorite restaurant haunts, brunette hair peeking out of a black suede cap.

"I would read a script and be so in love with that, and someone would be like, 'Hilary Duff? Oh no, we don't want her for that.'"

As bad scripts and rejections kept coming, Duff decided to stop the balancing act and put 100 percent into her music career.

Working again with songwriter Kara DioGuardi, she plunged into recording "Dignity," which was released this week. It's a club-oriented record filled with pulsating grooves, but also tackles some of the more serious issues she's faced since her last record, including a breakup with Good Charlotte's Joel Madden and her parents' split.

"Every experience that I had for the last two years, they were certain things that made me want to write about in song," says Duff, who co-wrote all but one song on the disc — the first time she has written so extensively for a CD. "I really got to have fun. It's a new side of me and part of me. All the songs are so self-explanatory. It was very liberating — writing it is like a therapy session."

"She was very honest about where she was in her life, and very open, which made it very easy to collaborate," says DioGuardi. "I think she's really become an adult on this record. She's a young adult, in the way that she feels, in the way that she acts, in the way that she interprets what she's singing about."

While recording "Dignity," Duff was in transition, in both her personal life and her professional one. One of the bigger jolts was the end of her romance with rocker Madden. Though the pair first raised eyebrows because of their seven-year age difference — he was in his 20s and she was under 18 when they first started dating — they seemed like a solid couple, and he even worked on her greatest hits disc, providing an edgier sound then the bouncy pop that had become her signature.

But Duff says she broke it off last year when she had a feeling that "this isn't right anymore. I didn't know how to trust that feeling but I knew I had it."

Duff still speaks warmly of Madden ("I will always love him, he was a wonderful person") and admits it was hard to see him move on so quickly to his current flame, tabloid magnet Nicole Richie. But Duff says she's happy being single.

"I want to be alone — I wouldn't imagine dating someone," she says. "It was hard, it is painful, I still get really sad, but I feel empowered."

She went through another tough breakup, though not her own: the dissolution of her parents' marriage. Though Duff doesn't go into details, she admits the song "Gypsy Woman" was in part inspired by the family drama.

"It's about a woman who breaks up a family. It's weird, because you feel like it's a cover-up — were they happy?" Duff asks of her parents' marriage.

Talking to friends about your crises is one thing; putting it on a record for the world to hear is another. At first, it was hard for Duff, who admits to growing up "cautious," wary of putting her public life on display. But eventually, Duff decided to channel her feelings on "Dignity": "'What am I hiding for?'" she asked herself. "I think it's easier to open yourself up through music."

While Duff was able to express different emotions on record, she found it difficult in her acting career, mainly because most of the offered roles kept her in "Lizzie McGuire" mode, with fluffy, family friendly films like "Cheaper by the Dozen."

"I really didn't want to do that," says Duff, still frustrated at the thought. "I wanted to challenge myself and do something unexpected, and also wanted to be excited about it."

She even began to doubt her acting skills. "'Nobody thinks I'm good, nobody thinks I can do anything different,'" she recalls thinking. "I felt kind of in a weird place. That's when I started making my records."

It wasn't until she was a month deep into recording "Dignity" and totally focused on her recording career that a film project stirred her interest: "War, Inc.," written by John Cusack, who also stars in it. It was Cusack who sought Duff out, but she almost passed — he wanted her to play a pop singer.

"But then once he talked to me on the phone ... (and) after I read it, I had to do it," she says of the part, an oversexed eastern European superstar.

She took a break from recording her album to shoot the movie in Bulgaria; she describes the shoot as a "life-changing experience."

"Going up there, I was a little intimidated and scared. It really just reassured me. It kind of brought back the passion I knew I had," she says of the movie, which does not have a release date yet.

Duff brought back that passion when she went back to work on "Dignity." DioGuardi, who has worked with Duff since her first record, says she's noticed a change in the performer over the past year.

"She's definitely now in my opinion has a more active role in her career, and she's still the same sweet compassionate girl that she is," DioGuardi says. "I think she's just taking more control of her life."

She also gained more confidence — enough to again tackle those twin career goals.

"Before, I definitely considered myself more of a singer. I think definitely since I did the movie I was like, 'I'm an actress.'"