Charlize Theron thinks she plays evil characters well because she is a ''bitch''.

The 36-year-old actress stars as the wicked stepmother Queen Ravenna in forthcoming movie 'Snow White and the Huntsman', and she believes her current run of portraying ''evil'' alter-egos is down to the current period in her life.

When asked how she manages to play evil really well, she replied: ''That is because I am a bitch! No, someone was saying to me, 'You have been playing a lot of evil and bitchy characters,' and we came to the conclusion that Picasso had his blue period and that this is my bitch period.''

Charlize found it was ''a lot of fun'' to scream at people all day while portraying the queen, but she was ''Dangerous'' on set and came close to causing some real damage with her crown.

She added to Britain's HELLO! magazine: ''It was amazing that we got to do this. I got to play all day. I got to put a crown on my head and scream at people - that was a lot of fun.

''Have you seen the crown? It is so pointed, I am dangerous. When we were not shooting I would forget it was on my head and I would bend down and nearly poke somebody's eye out with it.''

The blonde beauty - who recently adopted four-month-old baby boy Jackson - believes the film will be popular with children, despite being a ''dark'' version of the classic 'Snow White' fairytale.

She explained: ''The only thing I will say it that it is dark. It is a dark, realistic version of the story. The kids are going to love it.''