After 17 years of sobriety, injuries from a 2007 motorcycle accident left Tom Arnold hooked on painkillers. He's been clean for a year now, thanks to close friend Dax Shepard. "He really stood by me and helped me during my relapse," Tom tells TheFix.com.Just in time, too. Tom's new movie, Hit & Run, started shooting the day after he got clean — and Dax helped keep him that way. "When you're shooting a movie and it's hot and uncomfortable," explains Tom, "you've really got to stay on an even keel, and he helped me with that."Next up for Tom is a hosting job on CMT's new reality show, Redneck Rehab, in which city people are confronted by friends and family who want them to return to their country roots. "Because I grew up in a small town and don't get back there enough," says Tom, "I connected to how these families miss each other."