The Mexican director behind road movie Y Tu Mama Tambien has been signed up for the third Harry Potter movie, The Prisoner of Azkaban.

Alfonso Cuaron, whose last film was described by some as "erotic" will start work on the new film in the UK early in 2003, Warner Brothers announced.

Chris Columbus, who directed The Philosopher's Stone and its forthcoming sequel, The Chamber of Secrets, will produce the third film, along with David Heyman and Mark Radcliffe.

Cuaron said he was "so pleased" to take over the Potter franchise.

"It has captured the imaginations of many people, myself included, and I am so excited to join an amazingly talented cast and crew," he said.

'Compelling'

"To be able to add my own contributions to this rich and creative material is a wonderful opportunity and I know the collaboration will be a great one."

Lorenzo di Bonaventura, executive director of the studio's Worldwide Motion Pictures division, hailed the 40-year-old's appointment.

Kenneth Branagh stars as Professor Gilderoy Lockhart

He said: "We have prided ourselves on fulfilling our promise to the millions of fans to remain faithful to JK Rowling's beloved books.

"We are certain that Alfonso's gifts as a director will sustain that commitment and continue to bring the adventure and fantasy of this wonderful series to life in even more compelling ways."

Columbus added: "I am thrilled that we have found someone as talented and inspired as Alfonso to take over the reins as director. It will be a pleasure to work with him on this project."

Radical

Azkaban - set for release in summer 2004 - is expected to be darker than the first two films. The story centres on Sirius Black, an escaped mass murderer who is stalking Harry.

The Potter films mark a radical shift for Cuaron, who was unhappy that Y Tu Mama Tambien (And Your Mother Too) received an 18 certificate in the UK.

Critics described Cuaron's film as an "outrageously, uproariously sexed-up piece of work".

The movie-maker has also directed the modern day version of Charles Dickens's Great Expectations, starring Gwyneth Paltrow and Ethan Hawke.

But he has experience in making films aimed at younger people, having directed 1995 children's fantasy movie A Little Princess.