Charlize Theron has ''no diva blood,'' according to her co-star Rex Linn.

The 57-year-old actor thinks the South African beauty, whom he stars alongside in 'A Million Ways to Die in the West,' is one of the most down-to-earth actresses in Hollywood.

Asked what it was like to work with the Oscar-winner, he told E! News: ''Fantastic. She was great. She was one of the guys. She really is. There's no diva blood going on in her whatsoever. She's a consummate actor and she's fun as hell, really really great.''

But Rex admits he was initially surprised by the 38-year-old star's relaxed attitude.

He explained: ''I didn't know what to expect. But with an actor of her calibre you never know what to expect but she was one of the dudes, man. She's awesome, she's fantastic.

''When she'd come on the set it wasn't like [whispers] 'OK Charlize is on set' she'd just come on the set with the guys and it was like 'What's happening dudes. Let's do this, let's have some fun.' You know she's just one of us. It was always relaxed it was never any of that walk lightly around her kind of thing, which makes it even better.''

Meanwhile, Charlize was nervous about her boyfriend, Sean Penn, seeing the new movie even though she brought him to the Los Angeles premiere on Thursday night (15.05.14).

She said: ''Yeah you always get nervous. You know my whole family is here and some of my best friends who worked on the movie and it's that final release that you send something that you really love out there but it's still subjective and people are going to see it and think something of it. But I love this movie. So I am really excited to share it with everyone I'm here with tonight.''