The wildly popular fitness guru, known for his boot-camp style P90X fitness program, actually had his sights set on becoming an actor after graduating from college. But after moving to Los Angeles in the 1980s, Horton began working out at the legendary World Gym in Venice, California. By the late '80s, Horton had become an established personal trainer—helping to tone the bodies of numerous celebrities and athletes. His list of famous clients include: Rob Lowe, Sean Connery, Bruce Springsteen, Usher, Tom Petty, Billy Idol, and Sheryl Crow. His success as a motivator and renowned expert in the fitness field fueled the sales of his exercise DVDs and created a massive legion of followers. Just how successful is the Tony Horton franchise? It's estimated that his catalog of fitness programs has exceeded $500 million in sales.