Rihanna and Chris Brown

When Rihanna began dating 18-year-old R&B star Chris Brown four years ago, the teenage couple seemed like a great match. "He's one of my closest friends in the industry," Rihanna told Allure magazine in 2008. "He makes me feel like a teenager. I have to act and think like an adult so much. He makes me feel young again." But their relationship ended in violence in February 2009 when Chris was arrested and charged with assaulting Rihanna. He was later sentenced to six months of community service and placed on probation for five years. The shocking incident stunned the showbiz world, but Chris and Rihanna have since rekindled their friendship and are even rumoured to be considering giving their relationship another go.