Katy Perry Covers Rihanna's 'Only Girl In the World' (VIDEO)
Katy, 26, sang an acoustic version of Rihanna's hit song on the Barbadian singer's birthday on Sunday, February 20. At the time, Katy was kicking off her "California Dreams" tour in Portugal but she didn't let that stop her from celebrating RiRi's birthday in style.
What do you think of Katy's version of Rihanna's song? Share your thoughts in the comments.