David Thewlis is a well-known English character actor. You may remember

him as the voice of the earthworm in

"James and the Giant Peach" or as

the cabdriver in "Black Beauty."

In "Harry Potter and the Prisoner

of Azkaban" he's Professor Remus Lupin,

the kindly new Defense Against

the Dark Arts teacher who

has his own dark secret.

(Alert: For the two KidsPost readers

who are going to see the movie

but have not read the book,

stop reading right now.)

Thewlis, 41, talked to Bridget Byrne

about his role in the third movie

set at Hogwarts School of

Witchcraft and Wizardry.

How much of you as a werewolf do we get to see?

Most of the role is about showing the kindness of Professor Lupin's character. I'm sort of a Mr. Chips, a gentle, much-loved teacher -- that's interesting because the Dark Arts teachers before me were not loved.

What happens when finally he's revealed as a werewolf?

It took a full seven hours of make-up [along with special effects]. My face splits apart -- though I think they've edited that down a bit, because it looked too gruesome. It's very quick -- human, human, human, then teeth and eyes [change], a hunchback bursts through my jacket, my fingernails grow and all my clothes fall off and . . . I become all hairy!

Why did they offer you this role?

I don't really know. I had been considered for the role of Professor Quirrell [which Ian Hart played in the first movie, "Harry Potter and the Sorcerer's Stone"], so I suppose somebody obviously likes me. I felt an enormous responsibility because internationally there's a real passion among kiddies for these books. When I went online to do research about werewolves and stuff, I found all this e-mail chat saying things like, "Who is this person playing Professor Lupin? We want someone good-looking, like Jude Law!"

What do think is very different from the previous two movies?

I think it's very noticeable that the kids are grungier. You see them in clothes like track-suit tops, rather than always in school uniforms. They don't look so much like Hollywood's idea of school kids. They are much more like kids in reality. Especially Daniel [Radcliffe], who anyway is a little bit of a rocker, really cool!

David Thewlis plays Professor Lupin, the new Defense Against the Dark Arts teacher in "Harry Potter and the Prisoner of Azkaban," coming to theaters tomorrow. Above, Lupin talks with Harry (Daniel Radcliffe).