When Tom Arnold signed to star in his first HBO special, The Naked Truth, he decided to see his inevitable critics and raise them one. ''I don't know if I have any credibility without you,'' he whines to wife Roseanne Barr in the show's opening scene. ''I'm sick and tired of you riding on my coattails,'' she snaps.
''I wanted to take care of it right off the bat,'' says Arnold, who married Barr in 1990 and is a producer on her ABC series, ''but it's possible to overdo the joke, too.'' Arnold's real response to his detractors is the rest of The Naked Truth, in which the 32-year-old comedian roams Los Angeles in search of solutions to crime, pollution, poverty, and other world crises. Among the highlights is Arnold's take on the cloth vs. disposable diaper debate, in which he interviews hilariously straight-faced spokesmen (the real thing, not actors) for both sides. ''It's weird to talk to two people in the same business telling you exactly opposite things,'' he says, ''but Hollywood has made me used to it.''
The Naked Truth also includes a scene in which Arnold, who says he overcame a widely publicized cocaine habit 16 months ago, delivers an anti-substance abuse message to a group of teens. It's an abridged version of a speech that the comedian has actually given, but the kids in this special don't seem particularly interested. After Arnold delivers his heartfelt plea, one boy raises his hand. ''Who's fatter,'' he asks, ''you or John Goodman?''
''Actually,'' says Arnold, ''they asked some pretty decent questions. Of course, we cut those out.''