The show must go on, and the next Harry Potter film will go on with Oscar winner Jim Broadbent will take on the role of Horace Slughorn in "Harry Potter and the Half-Blood Prince."

"He's a retired teacher of magic who's drawn back out of retirement because he's got some secrets they need in the battle against the Deatheaters," Broadbent told the Dark Horizons Web site. "He's quite star struck as a teacher and he's drawn back into the fold because he likes to notch up celebrity students, and he's drawn back by Harry."

Rehearsals have already begun for the sixth film which will star Daniel Radcliffe, Emma Watson and Rupert Grint, and Broadbent -- best known for work such as "Moulin Rouge" and "Iris" -- said he's already suffering through "endless costume fittings and makeup."

Some of the clothes that he has been trying on are "tweedy sort of things with a bit of padding," Broadbent said. "He's an older man. I'm aging up again."

Broadbent has appeared in more than 100 films and television productions, including the "Chronicles of Narnia" and "Robots."

"Harry Potter and the Half-Blood Prince" is being readied for a Nov. 21, 2008 release, one month before "Star Trek XI."