Cast member Emma Watson poses during a photocall for the film 'The Bling Ring' during the 66th Cannes Film Festival in Cannes May 16, 2013.[Photo/Agencies]

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.

Emma Watson for 'The Bling Ring' in Cannes

"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, dressed in a short, black dress and black stilettos, told a news conference on Thursday where her presence creating a frenzy among photographers.

"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.