There are things Vin Diesel doesn't want you to know about Vin Diesel. His real name, for one (that would be Mark Vincent). His ethnic background, for another (half African-American, half Italian-American, or so we hear). If it were up to him, you probably wouldn't be reading his age right now (35). Even his hair is shrouded in mystery: He keeps his head shaved so smooth that not even his stylist knows for sure how much Diesel actually has.
But there is one thing about Vin Diesel that Vin Diesel has never been shy about sharing -- even when nobody is listening. ''I've always been certain that I was going to be a movie star,'' he says, his voice such a deep, low rumble it's a wonder it doesn't set off car alarms. ''Even as a kid I knew it. People keep asking if I've changed since becoming a celebrity. But I haven't changed because I've always thought I was a celebrity. It was the rest of the world that hadn't figured it out.''
The world, it seems, is about to get a crash course. The first full-scale Diesel-powered vehicle -- a $90 million contraption called ''XXX'' -- opens Aug. 9, loaded with all the extras: booming pyrotechnics, wall-to-wall gunplay, and even a noisy opening sequence featuring the German industrial-metal group Rammstein. It will, if nothing else, be the loudest movie of the summer.