Presto! New Characters

Look who's showing up at Hogwarts this fall.

Horace Slughorn
Jim Broadbent
Retired, Slughorn has been pressed back into service as the new Potions professor. (Snape is now teaching Dark Arts.) Slughorn's memory is crucial to Harry's growing understanding of Voldemort. ''But he doesn't want to remember,'' says Broadbent (Moulin Rouge). ''He lives in complete denial of reality.''

Lavender Brown
Jessie Cave
By turns giggly and bossy, Lavender pursues Ron, who foolishly indulges her interest just to make Hermione jealous. ''When I first read the part, I thought, 'Oh, this is the girl nobody likes,''' says Cave, 21, who makes her film debut. Luckily, the cast ''couldn't have been more welcoming,'' she says.

Tom Riddle
Hero Fiennes-Tiffin
The boy playing Voldemort as a child is, in fact, the nephew of the actual Dark Lord, Ralph Fiennes. ''But that's not why we gave him the part,'' says director David Yates. He credits Hero's ability to find ''the darker spaces'' in his line readings. Still, he says, the family resemblance was ''a clincher.''