By Nesta McGregor
1Xtra entertainment reporter
Harry Potter stars on new movie
There are steamy kissing scenes, a love triangle and an overdose of home made drugs.
It sounds more like an episode of Skins but this is Harry Potter and the Half-Blood Prince, the sixth movie version of J. K. Rowling's novels.
Harry, Ron and Hermione are all back with the film getting its world premiere in London on Tuesday evening.
Twenty-year-old Rupert Grint, who plays Ron Weasley on screen, is brought back from the dead by Harry Potter after taking a lethal cocktail of potions.
The actor's also been recovering in real life after getting swine flu. He said he was a bit worried when the doctors first diagnosed it.
"It was quite scary when they first told me I had swine flu 'cos obviously, what's been in the press and stuff," he said.
"And it was honestly fine. It was just a bit of a sore throat."
Harry Potter and the Half-Blood Prince sees the boy wizard and his mates trying to extract a memory from an old teacher at Hogwarts.
With it comes the secret of how to defeat Lord Voldemort.
As usual Ron and Hermoine are not far from Harry's side, even though Ron has other things on his mind - like being the centre of a love triangle.
The movie has been given a PG rating, even though critics claim it's the darkest and most sexed up movie to date.
Daniel Radcliffe reckons the steamy kisses and growing suspense won't alienate younger fans.
"I'm sure they'll be able to cope. And if they don't like it, just close their eyes and then open them again in about a minute or so, and then rejoin the film. It's fine.
"I really don't see that as being a problem."
Cast and crew from the new Harry Potter film will wear white ribbons on their wrists at the film's world premiere on Tuesday night as a mark of respect to murdered actor Rob Knox.
The 18-year-old plays Marcus Belby in the movie. He was stabbed five times outside a bar in Sidcup, Kent, last May days after finishing the movie.
Daniel Radcliffe, who plays Harry Potter in the series, said Knox's death had hit the whole cast.
He said: "I won't pretend I knew him incredibly well, or was his best friend on set, but I knew him and liked him, and what happened to him was obviously tragic and awful."
Knox's family watched the new film at a private showing ahead of the premiere.
Emma Watson is back as bookworm Hermoine. She thinks this film is actually a bit lighter than recent Harry Potter films.
She said: "It was nice to be back and to know that this film is, to me, more of a romantic comedy than ever before and that we would have a chance to focus more on that side of things.
"Sometimes I have to bring myself back with Hermione, because she is so innocent and so naive and she really is very vulnerable in this film.
"She really does get her heart broken by Ron and Lavender and that whole situation."
The films, the first five of which have earned around £2.7 billion at the box office, are based on British author J.K. Rowling's seven-book Harry Potter series.
They've sold an estimated 400 million copies worldwide.
There will be eight films in total, with the final volume, Harry Potter and the Deathly Hallows, divided into two.
Director David Yates said: "We're working at the moment on Deathly Hallows, and I think we're all aware that this great juggernaut is reaching the end of its journey in a way.
"We finish shooting next spring and everybody comes to work... with that knowledge in the back of their mind."