AceShowbiz -

The wholeness of "Harry Potter" principal cast is threatened to crack. Emma Watson, who is known to play Hermione Granger in the widely-popular film franchise, shockingly told Newsweek recently that she has not yet committed to star in the upcoming installment of the series, "Harry Potter and the Half-Blood Prince."

"I don't know yet," the 16-year-old actress admitted earnestly upon being asked about her involvement in the film. "Every film is such a huge production, and it's a long time."

Responding to Watson's statement, "Harry Potter" producer David Heyman has openly shown his reaction, saying that losing her "would be a hard thing to change and it would be disrupting", but the man on the other hand also revealed that he is "cautiously optimistic that it will work itself out."

If Hermione is indeed recast, this will be the second cast change for the franchise after the taking over of Albus Dumbledore role by Michael Gambon from Richard Harris. Gambon assumed the part in the third film, Harry Potter and the Prisoner of Azkaban, following Harris' death in October 2002 because of Hodgkin's disease at age 72.