Over the past few weeks, producers have been visiting schools across the country searching for someone to play Luna Lovegood in the fifth movie.
At Sunday's premiere, producer David Heyman told CBBC Newsround Online that the search was nearly over.
They are now choosing from a shortlist of five hopefuls.
"We've narrowed it down to a handful of people for Luna," he said. "I haven't seen them though. [Director] David Yates has been doing the casting."
It's believed that following on from the school search along with applications sent in to the studios, there have been a number of casting sessions and workshops in London with girls being considered for the part.
David Heyman also confirmed that they had specific people in mind for other parts in the movie. Imelda Staunton is at the "forefront of the search" for someone to play Professor Umbridge.
And two actors are in talks to play Kingsley Shacklebolt and Tonks.
Anna Friel, the partner of Lupin actor David Thewlis, has been rumoured to be in line for the role of Tonks, but David Heyman said that she definitely wasn't being considered for the part.
Filming on Harry Potter and the Order of the Phoenix will begin in February 2006.