/REUTERS, CANNES

British actress Emma Watson has turned to crime in her latest role as part of a celebrity-obsessed teenage gang robbing their Hollywood idols' homes in a film that made its debut at the Cannes film festival on Thursday.

"The Bling Ring," written and directed by Sofia Coppola, is based on a real-life gang fixated by glamour who tracked their targets' whereabouts online and stole $3 million of luxury goods from celebrities including Paris Hilton and Lindsay Lohan.

Watson, 23, proved her days as Hermione in "Harry Potter" are long gone as she donned skimpy outfits and perfected a Los Angeles accent to play a fictitious version of one of the Bling Ring gang, who were caught in 2009 and sent to jail. She said her main challenge was to work out why these teenagers, from mainly wealthy backgrounds, were so preoccupied with celebrities. Her research involved watching reality TV shows like "Keeping up with the Kardashians" and "The Hills."

"I enjoy the chance to transform into new roles and work with new creative people," Watson told a news conference on Thursday. "Harry Potter seems like such a long time ago," she said.

"The Bling Ring," which opened the Cannes category "Un Certain Regard" for emerging filmmakers, starts with the teenagers seeing on a gossip website that Paris Hilton is in Las Vegas and guessing she would be the kind of person to leave a key under the mat.

They find her address and in they sneak, returning several times to party in the house and then to other celebrities' homes, helping themselves to Birkin bags, Louboutin shoes, Rolex watches, bling and cash to fund their drug- and alcohol-fuelled party lifestyle, boasting about their acquisitions on Facebook. Even when their make-believe celebrity world comes crashing down, the teenagers seem oblivious to the gravity of their crimes and more interested in hyping their newfound notoriety.

Alongside Watson, Katie Chang plays Bling Ring leader Rebecca, while Israel Broussard is her submissive lieutenant with Taissa Farmiga and Claire Julien making up the gang.

The film received favorable reviews after a press screening on the second day of the 12-day Cannes festival, described as a "wily critique of celebrity culture" and an "intuitive and atmospheric tale" with a great soundtrack. This was a welcome reaction for the American Coppola, whose third film "Marie Antoinette" was booed in 2006 when it made its debut at Cannes.

Coppola said "The Bling Ring," which opens in the United States in June, was a comment on culture today -- both the teenagers' obsession with the celebrity life and the celebrities themselves with houses overflowing with expensive goods. Paris Hilton, the celebrity heiress, allowed them to film in her real home with shots of a room wall-to-wall with shoes and a pole-dancing table in the middle of a nightclub area. "The world this film shows is a world of excess," said Coppola. "[Paris Hilton's] house is very exotic. I have never seen anything like it before."

Coppola, 42, whose film "Somewhere" won the top prize at the Venice Film Festival in 2010, said she met two gang members as she wrote the film to garner extra details but she changed the names in the movie, not wanting to add to their celebrity. She dismissed complaints by some of the Bling Ring members that the film was "trashy and inaccurate." "It is not a documentary. I am not too concerned with their reaction," she said.