Actress Sarah Wynter has her hair measured on a daily basis - because her role on hit TV show 24 demands that her appearance never changes.

Because all 24 episodes of the gripping drama are set on the same day, actors have to maintain physical continuity to make the show believable to viewers.

She says, "The fans are so eagle-eyed. If my hair has grown at all, it gets a trim."

The series' bosses also keep a close watch on actors' weights.