The 29-year-old sparked flames with the Your Body Is A Wonderland singer initially through love letters.
According to Katy she 'had a long courtship [with Mayer] before anything was [public]' over the summer of 2012.
Long courtship: Katy Perry has revealed she and
John Mayer only exchanged letters for months, pictured in London earlier
this month
The Roar singer told the November 8 issue of Entertainment Weekly that she was pen pals with her 36-year-old beau long before they began a full on romance.
Perry told the publication that her new song Legendary Lovers came out of that extended courtship.
Katy explained: 'I actually wrote it in an email one time, and after I wrote it I looked -- we had a long courtship before anything was [public], just writing letters to each other -- and seeing "legendary lovers," it sounded so nice.'
Former flame: before John Perry was married to Russell Brand, pictured in Los Angeles in December 2011
Adding: 'Some things float into my mind, and I process them, and [then] I make songs about them.'
In the track off of her new album Prism, Perry croons: 'Never knew karma could be so rewarding and bring me to your life/ Maybe this is the beginning of something so magical tonight.'
The romance between Perry and Mayer came soon after Katy finalised her divorce from her husband of 14 months Russell Brand in early 2012.
A long list: Mayer has previously been linked to Taylor Swift, pictured in New York in December 2009
Mayer famously dated Taylor Swift, Jennifer Aniston, and Jessica Simpson before striking a romance with the Fireworks singer.
But the two may be headed down the road to marriage, as an insider recently told Us Weekly: 'Everyone knows it's just a question of when John will propose.'
And the two are making sure to keep their flame alive as Katy travels the world to promote her new album Prism.
Fated: A source close to the couple says they believe they 'are meant to be together'
The source told UsWeekly that the two lovebirds 'realize they must be together'.
And in that effort they 'Skype and text all day' to stay in touch.
Inspiration: Katy's new song Legendary Lovers off of her Prism album is based on her love letters with Mayer
