Kelly and Katy would be powerful
Despite those that say Katy does not have a strong enough voice for Kelly, if you heard Katy's performance at the Grammy's you might change your mind. I think "Part of Me" took everyone by surprise! And ya gotta admit, the theme of both Kelly's hit "Stronger" and Katy's "Part of Me" are very similar!
Please take a moment to listen to check out Katy Perry's BRAND NEW single "Part Of Me": http://vevo.ly/yHKLxN