Los Angeles ? “Harry Potter” has a new schoolmaster: Michael Gambon.

The Irish-born actor is replacing Richard Harris, who died last year, as Albus Dumbledore in the third installment of the “Harry Potter” series, Warner Bros. announced Friday.

“Harry Potter and the Prisoner of Azkaban” is filming in England, and Gambon’s casting had been a closely guarded secret. Other possible candidates for the role included Christopher Lee, Ian McKellen and Peter O’Toole.

Gambon, 62, is best known for his roles as the wealthy murder victim in 2001’s “Gosford Park” and the sinister landowner in 1999’s “Sleepy Hollow.” He also starred as President Lyndon Johnson in the 2002 TV movie “Path to War.”

Harris, who died in October at 72, was best known for playing combative, iconoclastic characters in films such as “This Sporting Life,” “Unforgiven” and “A Man Called Horse.”

Warner Bros. also announced that Gary Oldman would play the “Prisoner” of the title, a mysterious character named Sirius Black who escapes from the magical prison of Azkaban and seems to be stalking Potter and his friends.