"God knows she's had everything said about her. This is a fun rumour. But no, we have no idea where it came from."
Katy also joked that she is "swollen everywhere" as she awaits the birth of her first child.
She quipped: "I am going to be 190 pounds. I am large and in charge.
"Everything is swollen. My hands are swollen. My feet are swollen. I am in sandals, whatever."
Meanwhile, Katy recently revealed she calls her unborn child 'Kicky Perry'.
She shared: "I am waddling like a duck! I'm breathing heavily, I'm a full-on mouth-breather. And um yeah, it's loud and obnoxious and, oh my God, I just eat so much flavoured ice! It's like put all the ice in my mouth, right now!
"I call her Kicky Perry sometimes. I love a pun but I'm really active right now and, you know, my doctors are like, 'Stay active, you're good to go, girl!' And so I've been dancing, I've been singing a lot."
Katy also admitted she's grateful that Orlando - who has Flynn, nine, with ex-wife Miranda Kerr - already has parenting experience.
She said: "The good thing is that he has a kid that's nine. And he's been through it. So when we were going to pick out strollers, he knew exactly the stroller. And like, some of the strollers are very chic, they've got leather handles and blah, blah, blah. And I was like really drawn to them right? And he's like, 'No, let me show you what the stroller is. It's this one that you pick up in the middle and it collapses and it's like, 'Bang, bang', it's like an umbrella'.
"I was like, 'Oh my God, I'm so grateful that you know this, 'cause I would have gotten some, you know, large hunky thing' and that is avoidable because he's already had a test run so, I'm grateful for that."
