FOX has given a seven-episode order to the 20th Century Fox TV-produced series.
Dushku will play Echo, part of a community of "dolls," young men and women who are imprinted with new identities and false memories to fulfill a variety of sensitive assignments. None of the "dolls" have any memories of their own until Echo begins investigating their pasts.
According to The Hollywood Reporter, Williams will play "ruthless and protective" Adelle DeWitt, who runs The Dollhouse.
Dichen Lachman and Enver Gjokaj were previously cast as two of the dolls, while Fran Kranz will play a computer programmer who imprints the dolls. Tahmoh Penikett is set as an FBI agent trying to learn the truth about the Dollhouse.
Williams was last spotted in "X-Men: The Last Stand." She's best known for her roles in "The Sixth Sense" and "Rushmore."