TORONTO - Hilary Duff cemented her position as the ultimate Tween Queen last night with a show at the Molson Amphitheatre that provided everything her young audience could have wanted -- earnest smiles, poppy singalong choruses, girl-positive lyrics, dancing, sparkly lights and just the merest hint of rock 'n' roll.

In just a few years, Duff -- perhaps the only artist who could get away with putting out a greatest-hits collection after releasing just two albums -- has turned a starring role in the TV show Lizzie McGuire into a giant entertainment-lifestyle empire that encompasses movies, a new tween clothing line and a fragrance as well as music.

And last night's almost entirely female crowd proved their love by singing along, dancing, waving their glowsticks and screaming so much that earplugs were more of a necessity than at most of the summer's big rock shows.

What is it about Hilary that so enchants her fans, most of whom are a decade younger than she is? It's not the songs, which range from sub-Madonna dance-pop to sub-Avril pop-punk, or her voice, which is unremarkable at best.

Perhaps it's just that the everygirl Lizzie McGuire persona got so far into the teen-girl universe that they couldn't help but love everything Hilary did.

Still, a teen star's moment doesn't last forever, and already there are signs that Duff, who turns 19 in September, is looking to stretch beyond the role of pop princess.

Her latest songs, co-written with boyfriend Joel Madden of Good Charlotte, are punkier and more rock guitar-based than the fluffy early pop hits.

And both Duff -- dark-haired and wearing jeans, cowboy boots and a rock T -- and her black-clad band were clearly trying their best to look badass.

Opening with Wake Up, one of three new songs on last year's Most Wanted collection, Duff and co., went on to play rockier versions of hits like Getaway, Mr. James Dean and Do You Want Me, interspersed with big rock ballads like Cry, Someone's Watching Over Me and Hide Away.

She got virtually everyone in the place to raise their hands and clap during her catchiest song, Come Clean, and to dance with pure youthful joy to Party Up, Break My Heart and The Beat Of My Heart.

Perhaps Duff's finest moment, though, came during the song I Am, which she introduced by explaining that everyone has up and down days and should feel proud to be who they are.

Then she got all the tweens to announce that they are special, beautiful, wonderful, powerful, etc.

She may be encouraging them to beg their parents for low-rise jeans soon, but give her credit for that one little bit of positive thinking.