NEW YORK (Billboard) - As multimedia momentum goes, no one need teach 19-year-old Hilary Duff a thing.

For the past decade, she has built a career that began on TV, peaking in 2001 with her title role in Disney's 65-episode "Lizzie McGuire," making her a name brand among tweens.

Two years later, she recorded a full-length studio album, "Metamorphosis," which hit No. 1 on the Billboard 200, and the single "Come Clean" reached the Hot 100's top 40. The project sold 3.7 million copies -- and an MTV star was born.

With her upcoming album "Dignity," due April 3 via Disney's Hollywood Records label, Duff is coming out with the majesty of a high-class debutante. Duff co-wrote all songs on the album with A-lister Kara DioGuardi ( Gwen Stefani, Christina Aguilera), including the uptempo single "With Love." She is also promoting her new Elizabeth Arden fragrance, With Love, in addition to a clothing line, Stuff by Hilary Duff, available at mass-market retailers Wal-Mart, Kohls and Target.

"I know how lucky I am, but I've worked hard," Duff says. "Who could complain? I've traveled the world multiple times with so many rewards."

For the new album, Duff insisted on being more involved. "I knew I couldn't do it myself, but working with Kara allowed me to talk about things on my mind. It was one big therapy session." During the songwriting process, Duff endured the full scope of a relationship -- true love, doubt, breakup and resolution -- all of which play out during the course of the set's 14 tracks. (The other party was Good Charlotte rocker Joel Madden, who is now dating Nicole Richie.)

"People don't know a lot about my life, but these songs are self-explanatory. It was crazy to be in the midst of a loving relationship, then not knowing why you're still there, then not being in it. I cover these emotions and the feeling of being in the dark," she says.

Even so, the melodic template of the album is refreshingly dance/pop. "It's so different from my other albums, which were pop/rock," Duff says. "I didn't necessarily plan the album to sound like this, but it was so easy to write to."

Hollywood has a flush of promotion in place to ensure that "Dignity" reconnects fans who have grown up alongside the teen. Duff is co-hosting MTV's "TRL" the week before release, in addition to a three-episode reality special following promotion in Italy, Madrid and London. Yahoo also sent a crew to record a multi-episode series surrounding the project, focusing on Duff's musical maturity and refined womanly image. TV appearances include "Good Morning America," "Jimmy Kimmel Live" and "The Ellen DeGeneres Show," as well as commentary on VH1's "Maxim's Top 100" countdown.

Duff will support "Dignity" with a headlining tour, while she plans for further branding, including a line of eyeglass wear and youthful bedroom furniture to enhance Stuff by Hilary Duff. She also wants to develop "fashion-forward" clothing attuned to her age group.

But most of all, Duff hopes to maintain stance as a role model, based on the title track of her new project. "I don't insinuate that I have a ton of dignity -- come on, I'm 19 -- but it's something I strive to possess and important in how you treat others, how you handle your job and treat yourself," she says. "It's also something that can be easily lost. I hope I can hold on to dignity as I move forward."