Military service is mandatory in South Korea for all able-bodied males, aged between 18 and 35. The duration of service varies from branch to branch of the military -- with 21 months for Army and Marines, 23 months for Navy, and 24 months for Air Force. Exemptions are granted only to Korean male citizens with physical and mental disabilities. Over the years, there have been controversies regarding celebrities who try to avoid military duties (some even go as far as changing citizenship!) and also allegations of special treatment given to them. The government has since begun implementing tougher sanctions. Take a look at some of the Korean male stars who have enlisted these past few years and what happened to their careers after.