Sigourney Weaver is ''comfortable'' taking risks.

The 'Chappie' star believes she should always keep challenging herself when it comes to acting and switches between genres so she can avoid making the same films again and again.

She said: ''I think it's important never to repeat yourself, and that's why I've jumped from drama to comedy to sci-fi.

''I'm happy and very comfortable taking risks in my work. You've got to change it up and everyday go, 'I don't know whether I can do this' and that's why it's interesting.''

The 65-year-old actress also hailed Neill Blomkamp, the director of the film - where she plays CEO Michelle Bradley - as a ''mastermind''.

She shared: ''Neill's one of those masterminds. He's comfortable with all of the technology, not only classic science fiction technology, but what's really happening. He's also dazzling visually.''

She is also set to star in the new 'Avatar' films and whilst her character was fatally wounded in the 2009 outing, she insists ''no one ever dies in science fiction''.

She told the Nottingham Post newspaper: ''I just know I'm playing a really cool character so I'm kind of working on it to the extent of what I know.

''We haven't started (filming) yet, but when we do, we'll all probably disappear off the face of the earth for a year and a half.''