They travelled miles to audition for the part of Cho Chang - the Ravenclaw seeker who wins Harry's heart.
Cho doesn't appear in the movie for the third book Prisoner of Azkaban, but there was no way film-makers were leaving her out of Goblet of Fire.
A spokeswoman for Warner Bros. said around 3,000 hopefuls turned up.
"We hope to see everyone who comes along. We're going as fast as we can," she added.
Katie, 13, from Middlesex, reckoned she had a three-hour wait in front of her.
"I've done worse. I waited five hours to audition for S Club Juniors," she said.
"I'm just here for the experience."
Susan, 16, originally from South America, started queuing at 7am.
"It's really cold, but it doesn't matter. I've read all the books. I want to be her!"
Jess, 13, from Guildford, said she wasn't too bothered about getting the part - she'd been dragged along by her friends.
She was just going in for her audition, but she said she felt fine.
"I don't feel nervous. I'm just doing it for a laugh," she giggled.