Margot Robbie offered to shave her head for 'Z for Zachariah'.

The Australian actress, who stars in the new sci-fi drama alongside Chris Pine and Chiwetel Ejiofor, admits she was eager to distance herself from her sexy image as much as possible.

The 25-year-old beauty explained: ''I had just finished 'The Wolf of Wall Street' and it was great to do something different. The director asked if I'd dye my hair, and I said, 'I'll shave it off. Whatever you want!' I was keen on not being typecast.''

Margot also insists she is a tomboy at heart.

She said: ''I grew up on a farm in Australia, so I knew how to milk cows and ride tractors.''

The trio formed a close bond while filming the movie, and the actress says it helped them really feel like they were the only people left on the planet.

She said: ''Filming in New Zealand was extremely remote. We didn't have phone reception, so it did really feel like we were living in a post apocalyptic world.

''On Friday nights, we filled a bathtub with beers. We just hung out.''

But Margot missed Frosty, the dog in the film, the most after they wrapped up shooting.

She added to Us Weekly magazine: ''We lived together. It was weird to leave set without him, but I liked not having dog food in my pockets.''