The men behind Hilary Duff’s new movie War Inc. felt sure they’d have to rewrite some scenes when the squeaky-clean actress landed the lead - because they’d be too crude for her.

But the game actress/pop star shocked them by going through with the risque scenarios - which included performing mock fellatio on a fuel pump and dropping a live scorpion down her pants.

Writers Jeremy Pisker and Mark Leyner say, "We wrote a scene where her character gives a blow job to a gas nozzle, and when we got Hilary to do the movie, we thought, ‘Well, we’ve got to rewrite that.’ But she did it." And co-star John Cusack admits her fake fellatio was better than the one on paper: "She did it in a more sly way. She licked it (the nozzle) like an ice-cream cone. She did better than the script." When it came to the scorpion scene, Duff, who plays a wildchild Eastern European pop star in the film, had nothing to lose.

She explains, "I had done so much for this film by then, I couldn’t really say no." But Duff admits she was a little concerned her tough-talking, wild character would upset her fans: "I have to have this foul mouth, be this rude and crude girl who tries to be sexy but she’s so young and kind of vulgar."