And our potty Potter expert Lizo Mzimba has been digging around to get the freshest information about who's playing who.
We can now reveal that Colin Creevey, Harry's number one fan, will be played by 12-year-old Hugh Mitchell.
And Ginny will be played by Bonnie Wright - who appear briefly in the first movie.
A mysterious Myrtle
There's a interesting piece of casting for Moaning Myrtle, the ghost who haunts the girls' toilets.
She'll be played by Shirley Henderson who's 35 years old (yes 35!!!). She was last seen in Bridget Jones's Diary as Bridget's best mate Jude.
In the books, Myrtle is a miserable teenager. It'll be fascinating to see how she manages to play such a character.
Aragog uncovered
One time Hogwarts Headmaster Armando Dippet will be played by Alfred Burke.
And veteran actor Julian Glover will provide the voice of Aragog the giant spider.
He's best known for a small part as a villain in Indiana Jones and the Last Crusade - and was pretty scary in that too!!!
And despite the rumours flying around, Tom Riddle hasn't been cast yet.
Draco's dad unknown
As for whose playing Draco Malfoy's father, Lucius Malfoy, the internet's been awash with rumours that Richard E. Grant was going to take the role.
But when Lizo caught up with him a few weeks ago and asked him if he was set to play the part, Grant replied "Not that I've heard."
So, that'd be a 'no' then.
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