Full show replay: Katy Perry and John Mayer at the Grammys 2013 Katy Perry and John Mayer at the Grammys 2013 Katy Perry and John Mayer at the Grammys 2013 Katy Perry and John Mayer at the Grammys 2013 Katy Perry and John Mayer at the Grammys 2013 Katy Perry and John Mayer at the Grammys 2013