Thompson prepares for her Harry Potter role

Emma Thompson says she will be wearing “great, googly-eyed glases and Oxfam clothes” for her role in the new Harry Potter film, Harry Potter and the Prisoner of Azkaban.

The British actress will play Sybill Trelawny, the eccentric professor of divination at Hogwarts School of Witchcraft and Wizardry in the film, which is currently shooting at Leavesden Studios in Hertfordshire.

“I was hoping that at some point I’d be asked to do something in a Harry Potter film,” Thompson told journalists in London. “I’m doing it for my three-year-old daughter so that later she will be impressed.”

She joins a cast of new faces that includes Gary Oldman as Sirius Black, Julie Christie as Madam Rosmerta, Dawn French as “The Fat Lady” and Michael Gambon taking over from Richard Harris as Professor Dumbledore.

Thompson, who took a two-year break from work after her daughter was born, will soon be seen in Richard Curtis’s romantic comedy Love, Actually, playing the Prime Minister’s sister, who discovers her husband is having an affair.

Next year she will begin filming Nanny McPhee, a children’s story which she has been writing for six years.