Following K-Stew's split from Rob, the Twilight hunk was romantically linked to Katy, with the singer telling ELLE UK magazine she had to assure Kristen they were just pals.
K-Pez explained: "I sent her a text message saying: 'I know you’ve seen all this stuff but you know I would never disrespect you. I’m not that person. I’m just trying to be a friend to him but it is unfortunate that I do have a set of tits'."
As well as talking about R-Pattz, the Firework singer also addressed her split from John Mayer in February, stating: "He pulled away. That was a big hello for me.
"I realised I could lose the person I loved and I had to deal with some things, issues I think a lot of women have. You can be strong in one aspect of your life but submissive in another."
Perry added: "In relationships, it was hard for me to speak up and set boundaries. I think a lot of that was to do with the fear of loss.”
The 28-year old said: "I love her [Rihanna] and every time I see her, I’m reminded of the light that she has. There’s a lot of dark in this business.
"I know a lot of people out there with the most detrimental entourages – they are the root of their demise. It’s really unfortunate but you can’t save these people. My days of celebrity saving are over.”
See Katy Perry’s full photo shoot and interview in the September issue of ELLE UK, on sale July 31. Also available as a digital edition.