Oscar nominee Helena Bonham Carter is joining the cast of the fourth "Terminator" feature, now in production.

Directed by McG, the latest extension of the cyborg franchise is currently being called "Terminator Salvation" by The Hollywood Reporter, a tightening of the long-used "Terminator Salvation: The Future Begins" title.

The trade paper offers no details on Carter's part except to say that it is "small but pivotal."

Christian Bale is set as John Connor, the leader of the human resistance formerly played by Edward Furlong and Nick Stahl in earlier films. "Terminator Salvation" is reportedly shooting its exteriors in New Mexico, rushing to finish that portion of shooting before a potential actors strike.

The possibility of an interrupted shoot cost "Terminator Salvation" its leading lady last month when French actress Charlotte Gainsbourg left the production.

Warner Bros. will release the film in May 2009.

Carter was most recently seen in "Sweeney Todd" and "Harry Potter and the Order of the Phoenix."