Dragons, driving rain and a boy called Daniel.
It can only be the world premiere of Harry Potter and the Goblet of Fire.
Newsround Online's Clare Youell reports from the red carpet.
"Daniel, Daniel, Daniel, DANIEL!!!"
Wonder who they're after?
There were so many celebrities at the world premiere of Goblet, but the crowds pretty much wanted to see just one of them - a certain Daniel Radcliffe.
And boy has he come a long way since he first appeared at London's Leicester Square for the premiere of The Philosopher's Stone back in 2001.
Then he was the shy young man who'd been picked to play Harry Potter and looked like he wasn't sure how to handle his new-found fame.
Daniel with his co-star Katie Leung
But that kid is long gone.
Sporting a stylish green and black velvet suit, Dan looked every inch the star as he worked the crowds, painstakingly signing autographs and fielding questions from the world's media.
Speaking about his natty suit, Daniel told Newsround: "I think it's rather nice. I just wanted to go for something really quite bold, because it's the first time that everyone's seen me in a year or so, so I wanted to go for a very different look."
He admitted he still found the madness of the premieres a bit odd. "It's actually been slightly easier this year, but it doesn't get any less bizarre."
Bigger and bigger
Arriving within minutes of Dan were his two closest co-stars, Emma Watson and Rupert Grint.
Emma practically flew out of her limousine, and went straight over to the waiting crowds, where she spent ages signing autographs and beaming happily at her fans. She must have been freezing in her strappy dress but she showed no sign of the cold. The dress, she told reporters, was "vintage" and was a very lovely cream and red creation. Oooh!
"The premieres just get bigger and bigger every year," she enthused. "This is the world premiere and it's big and brilliant and fantastic!"
Rupert Grint joined Dan in sporting a velvet jacket, his a fetching shade of blue. "In a weird way the premieres are quite strange, even getting recognised is quite weird, but everyone's always really nice," he told Newsround.
His movie brothers, James and Oliver Phelps, who play Fred and George, caused a bit of a stir.
The real-life twins have to dye their hair ginger for the roles, but they both had dark brown locks! They looked totally, totally different.
"This is our natural colour, it's the first time we've had it for five years!" they told Newsround happily.
The Phelps twins with BROWN hair!
Another person the crowds were keen to see was newcomer Katie Leung, who plays the girl Harry has a crush on, Cho Chang.
Katie, who has never acted before Potter, looked stunned at all the attention she was getting.
"It's incredible. I'm really terrified. But it's exciting. I'm so glad to be here," she told us.
"Everyone's been telling me that it's going to be big. But I never realised that there'd be so many people."
Katie was wearing a gorgeous pale green dress and admitted to reporters she'd only bought it the day before in a "last-minute rush".
The crowds went crazy every time a new car pulled up on the edge of the square. Huge cheers went up for the other young heart-throbs.
The fans went Potter-crazy
The biggest crowd-pleasers seemed to be Tom Felton (Draco Malfoy), Robert Pattinson (Cedric Diggory), Stanislav Ianevski (Viktor Krum) and David Tennant (Barty Crouch Junior and Doctor Who!)
It was heartening to see, despite the huge stars these actors have become, how much time they spent with the fans, particularly as it was raining the entire time!
Almost all of the Potter stars acknowledged how long the crowds had been waiting in the freezing cold and spent as much time with them as they were allowed.
Of course, an event like this one attracts loads of celebrities too.
Madonna with her daughter Lourdes
At one point, a short, shocked silence fell over the crowd. There were whisperings and mutterings. And then an almighty scream erupted. The Newsround crew craned its necks along with everyone else to see who had arrived.
It was Madonna.
She'd bought her daughter Lourdes along, as she loves Harry Potter.
Even the superstars can't get enough of Pottermania!