The singer, whose divorce from the Brit was finalised last year (12), sneaked into the crowd at her then-husband's comedy show on a night off from her tour and she was blindsided when he began making fun of her during the gig.
Speaking about her ex-husband, Perry tells America's Vogue magazine, "(He was) hysterical in some ways. Until he started making jokes about me and he didn't know I was in the audience, because I had come to surprise him at one of his shows. So. Hysterical to a point."
The California Gurls hitmaker documented her efforts to make the romance work in her 2012 documentary Katy Perry: Part of Me, but insists she didn't deliberately exclude clips of Brand from the film.
She adds, "I have to claim my own responsibility in things (that led to the marriage breakdown). I do admit that I was on the road a lot. Although I invited him time and time again, and I tried to come home as much as I possibly could. You saw that in the movie... That wasn't edited to leave footage (of Brand) out - there wasn't any footage of him."
However, the 28 year old is confident she will eventually find true love: "I'm not in a relationship, I'm just on my own - I am myself in my own bed. I have to be happy being alone, and I am happy. I believe that I will be loved again, in the right way. I know I'm worth it."