Sexy Katy Perry Pictures

Katy Perry turns 28 today! It's been quite a year for Katy. She had nothing but success when it came to her career, having multiple singles off her Teenage Dream album make it to the top of the charts. She also embarked on an around-the-world tour and released her first movie, Katy Perry: Part of Me. She dealt with the breakup of her marriage to Russell Brand, but she may have found love again with new guy John Mayer. Katy was even able to celebrate John's 35th birthday earlier this month!

For Katy's big day, we've rounded up 28 of her sexiest moments. Click through to see them all — and happy birthday, Katy!