He says he gets letters from children all over the world, and sometimes they even knock on his front door, although he doesn't mind really.
'Big responsibility'
The third Potter film has a bit of a new look
Sir Michael - who took over the role after Richard Harris died - said it was sometimes a bit of a nuisance but it's important to keep smiling and be nice to his young fans.
He said: "My friends' children come round and see me now, which they never did before.
"Being Dumbledore is a big responsibility."
But playing Dumbledore obviously hasn't proven that big a job, because since filming began in February he's had time to make three other films!
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