What Scott Beaudet really wants is J.K. Rowling’s signature tattooed on his body.

The self-described No. 1 Harry Potter fan spent eight nights camped in blustery central London in hopes of snagging the author’s autograph, which he then wants to have inked onto his body.

“She could sign my face, and I would get it tattooed on,” he said jokingly. Sort of.

Beaudet, 18, from Vancouver, B.C., was the first fan to be let into the red-carpet area in Trafalgar Square on Thursday for one of the most extravagant film premieres London has ever seen.

With the world premiere of “Harry Potter and the Deathly Hallows: Part 2” on Thursday, and the film in U.S. and British cinemas July 15, Britain is in the throes of Potter mania as fans from all corners of the planet gather in the capital city to be a part of Potter history.

Attending the premiere was “very, very emotional,” a teary Rowling told the crowd of about 8,000, which seemed to well up with her and then began tweeting adulation using the hashtag #queenrowling.

Trafalgar Square is a resplendent setting that pays homage to Britain’s former military glory, but on Thursday it was transformed, with Daniel Radcliffe, Emma Watson and Rupert Grint and dozens of other cast members walking a half-mile-long red carpet, signing autographs — in some cases for hours — before passing through “Diagon Alley” to Leicester Square, where the movie was shown.

The fever pitch around the epic finale feels “the same as the last ones, but 10 times bigger,” Matthew Lewis, who plays Neville Longbottom, said in an interview Wednesday after a news conference.

“People have turned out not for the actors, but because they enjoyed the journey, they have seen themselves refracted through the prism of these characters,” said Jason Isaacs, who plays Lucius Malfoy, in an interview. Still, he said, that hasn’t stopped thousands of fans in London this week from spotting him on the street and becoming “so hysterical that they can’t talk.” (Talking to them in hopes of calming them down “doesn’t work. It gets worse.”)

Among folks gathered in London, it quickly becomes evident there are varying gradations of fandom.

There are those, like Beaudet, who want tattoos.

There are those who loved the books and films and maybe sat outside a bookstore at midnight waiting for “Harry Potter and the Deathly Hallows,” the series’ seventh and final novel. For them, this last film is eagerly anticipated and bittersweet.

And there are others somewhere in between, such as Vanessa Marasco, who deferred college for a year and spent her savings so that she could be within iPhone-photo-snapping distance of Grint. Attending the premiere, she said, was the only way to say goodbye.

“To be here, it’s like a real grand goodbye for me, and it might help me get over it,” said the 24-year-old, who flew from Melbourne, Australia.

Britons feel a unique sense of ownership in the franchise, perhaps because Rowling insisted that the films be made in Britain and cast with British actors. The movies, which have reportedly taken in more than $6 billion at the box office worldwide, have employed thousands in the nation’s film industry since the first was released in 2001.

While the mother of all Potter tours is likely at the Wizarding World of Harry Potter theme park in Orlando, fans here have been seeking out locations that inspired settings, such as King’s Cross station in London or the Great Hall at Christ Church College at Oxford University, and looking for the probable locations of the Leaky Cauldron pub or Diagon Alley along Charing Cross Road.

Others have sought out Potter-themed events like the wizard party last weekend at the London Film Museum, where fans were invited to come in costume and play the characters. Fans examined props from the films and posed against a green screen on Potter’s Quidditch broom.

Jennifer Smith, 63, a retired London teacher who attended the wizard party, stared blankly when asked why she brought her two grandchildren to the event’s “wand work” tutorial.

“For me, not for them. I’m the Potter fan,” said Smith, swishing and flicking her wand while earning plaudits from her instructor.

“It’s intense and quite strange to think it’s coming to an end,” said Holly Drysdale, 20, a law student from Newcastle, Australia, who was walking around London five days before the premiere with a lightning bolt drawn on her forehead.

Drysdale flew to London with her mom (who was gamely dressed as Professor Trelawney) just to be in the same city as the premiere but also to say goodbye to something other than the books and films.

“It’s like the end of your childhood,” she said.