Long before they were first photographed together in June of 2012, the two took their time getting to know each other, Perry revealed recently.
"We had a long courtship before anything was [public], just writing letters to each other," the "Roar" singer, 29, told Entertainment Weekly.
In fact, their letters were so romantic that they inspired a song on Perry's new album, "Prism," called "L egendary Lovers." (Sample lyrics include, "I want your energy, I want your aura/You are my destiny, my mantra.")
"I actually wrote it in an email one time… and seeing 'legendary lovers,' it sounded so nice," she revealed. "Some things float into my mind, and I process them, and [then] I make songs about them."
Lately, Perry has been open about her relationship with the "Who You Love" singer, 36, with whom she reconciled a few months ago after a brief split.
""I had a crush on him for a long time," she said recently. "And it just so happens we fit together great."