Pop star Katy Perry and ex John Mayer seemed to be having a friendly ... during which they collaborated on the song Who You Love from Mayer's Paradise Valley album. Mayer also played guitar ...

Mayer is a rock star from the 2000s most known for his hits “Waiting on the World to Change” and “Your Body Is a Wonderland.” The Independent reports that Mayer dated Swift from December 2009 to ...