Filming on the fifth Potter movie - The Order of the Phoenix - is due to start in January 2006, and there have already been lots of rumours about casting.
The script won't be finalised for months, so at the moment there's no information whether characters like Luna Lovegood will be in the movie.
But it's unlikely that there will be casting calls that anyone can go to.
A spokesperson for Warner Bros. told CBBC Newsround: "We don't automatically do open casting calls."
"We only do them when it's particularly challenging to find the correct person for a particular part."
That's why open casting sessions were held for the Patil twins, and for Cho Chang.
It was very difficult finding young actresses with the right appearance through acting agencies.
In the case of characters like Luna Lovegood or Michael Corner - if they're not cut from the film - it's almost certain they'd be filled without the need for open casting calls.
Filming on The Goblet of Fire will be drawing to a close soon.
Actor Henry Lloyd-Hughes plays Ravenclaw quidditch captain Roger Davies.
We have our first look at the actor from his appearance in BBC TV drama The Rotter's Club.
Davies takes Fleur Delacour, played by Clemence Poesy, to the Yule Ball.