It's easy to forget that some of Hollywood's biggest stars started their careers as members of the United States military. At one point in our country’s history, joining the military was a rite of passage for aspiring actors and musicians in America. During World War II, for example, more than 50 percent of Hollywood actors were in uniform by the end of their service. After the war ended, they returned home ready to make a name for themselves in show business. Here is a list of some of the biggest Hollywood names that held a gun on behalf of the US military and other cool allies.