The producers of the Sex and the City movie are so convinced it will be a hit, they have already begun planning for a sequel.

The movie's star, Sarah Jessica Parker--who has been filming the big-screen version of the hit comedy in New York City for the past two months--is said to be eager to exercise the sequel option written into her contract, which stipulates she will reprise her role as Carrie Bradshaw should studio bosses plan a film follow-up.

An on-set source tells British newspaper The Mail on Sunday, "The producers are already working on a script for a second movie--they are so convinced the first will be a hit. They are exercising the sequel option in all of the stars' contracts.

"They want it to be a franchise and think they can stretch it over at least three movies."

Sex and the City: The Movie is slated for release in spring 2008.