Rihanna turns 25 today, and to celebrate the singer's birthday, we've rounded up 16 of her most memorable red-carpet looks thus far. She's certainly taken a no-holds-barred policy when it comes to dressing, so let's just say, we've come to expect the unexpected — from the most glamorous renditions to the downright skin-baring sex appeal. Among her standout looks? Last year's formfitting reptilian Tom Ford number at the Met Gala and a daring white Adam Selman gown at the LA premiere of her film, Battleship. Most recently, she stunned at the Grammys in a custom red floor-skimming Azzedine Alaïa gown. Click through to see them all now.