WHAT SHE'S DOING Her MTV reality show is cozily scheduled right after sister Jessica's ''Newlyweds,'' but it probably didn't need the help. Raven-haired Ashlee replaces her sibling's whiny designer-handbag angst with weightier issues: chiefly, how can she prove herself as a serious singer-songwriter to those expecting Jessica's bubblegum pop?
WHY SHE'S HOT RIGHT NOW Watching the plucky onetime ''7th Heaven'' star struggle to extricate herself from her sister's shadow is compelling TV, and her music isn't bad, either. Her first album, ''Autobiography,'' debuted at the top of the charts this month.
BREAKOUT MOMENT The butterfly emerged from her cocoon when we saw the 19-year-old sing original material for the first time at Hollywood's Knitting Factory. After some initial fumbling (and almost taking a header across the stage), she found her inner rock star, bumping and grinding to the amazement of her bandmates. Even Jessica, blurry-eyed from laser surgery, lavished her with praise.