It's Rihanna's day to shine (bright like a diamond)! Turning 25 years old today, bad gal RiRi has much to celebrate. In the last month alone, she stunned onlookers with her GRAMMY Award performance of "Stay" and Bob Marley tribute, debuted her River Island collection at New York Fashion Week, and joined forces with MAC Cosmetics for a series of color collections launching later this year. From a never-ending series of top charting hits to ravishing style success after success, it's hard to believe Rihanna is merely a quarter of a century old. We can't imagine what headlines our favorite good girl gone bad will cause during her 25th year. More racy looks, brilliant dance jams, and unavoidable Chris Brown drama, we're sure. Happy birthday, RiRi!