STARDUST actor Charlie Cox is terrified of becoming a star, and is consulting pal Sienna Miller for tips on being famous. The British 24-year-old was plucked from obscurity to star in the Matthew Vaughn-directed fantasy film, and he confesses he is anxious about the impact it will have on his profile. Cox says, "Fame terrifies me. I can say that with honesty. I've met other young actors and spoken to them about it. I've been friends with Sienna for a while and we've spoken about it. "It's a hard balance to strike."