A veteran Academy Award nominee and a 14-year-old unknown will join the cast of J.K. Rowling's epic Harry Potter series as filming begins next week on the latest movie, producers said.

Luna Lovegood Credit: Warner Bros.

Millions of fans across the world are eagerly awaiting the adaptation of Rowling's fifth book - "Harry Potter and The Order of the Phoenix" - which sees the return of young actor Daniel Radcliffe in the title role.

Filming will begin Monday in Hertfordshire, a county in southern England. The movie is not slated for release until next year.

The plot centers on the arrival of Dolores Umbridge, an unpopular new professor at wizard academy Hogwarts. She will be played by actress Imelda Staunton, nominated for a 2005 Oscar for her performance in the bleak period drama "Vera Drake."

Potter also wrestles with his attraction to new character Luna Lovegood, a role taken by 14-year-old newcomer Evanna Lynch.

Lynch beat out 15,000 young rivals in an open casting for the part in Britain.

The last film in the series, an adaptation of the fourth book, "Harry Potter and the Goblet of Fire," was directed by Mike Newell and grossed over $285 million at the box office.

"The Order of the Phoenix" will be helmed by British director David Yates, who last year made the HBO movie "The Girl in the Cafe."