Now here's a way to set off some fireworks.
Maybe it was nerves at being on her estranged hubby Russell Brand's home turf, maybe it was the screaming assembly of fans (who she repeatedly implored to "shut up"), maybe it was…well, we're still not sure, but while talking about the possibility of making good on her long-promised collaboration with bestie Rihanna, Katy sent what some thought sounded like a not-so-subtle diss Beyoncé's way.
So, what'd she say?
When queried by DJ Fearne Cotton on her plans for teaming up with RiRi, Katy launched into an explanation of what type of song the duo wanted to make together…and what kind they had no interest in repeating. Let's just say, Beyoncé didn't fall into the former category.
"We collaborate on a lot of things, but not songs yet," Perry said of Rihanna. "We're planning on doing it…It's one of those things that's gotten so much build-up, that if we don't deliver the best song…"
And here's where things got a little dicey, as the blue-haired pop star compared what kind of song she thinks is best with, well, the kind of song that is not the best.
"I was telling her, you know that Eurythmics song with Aretha Franklin, Annie Lennox, 'Sisters Are Doing It For Themselves'? That's like the kind of song that I'd want to do instead of, like, 'Hips Don't Lie,' which was still a great song by Shakira and Beyoncé. I mean, not 'Hips Don't Lie,' what's that duet? 'Beautiful Liar.' I knew there was a 'lie' in it, something about that."
No lie, intentionally or not, that came off a little harsh. And then she carried on.
"I loved it, but I definitely want to do something that is just kind of like, so iconic," she went on, not making things any better.
As for her team-up with Rihanna, don't pencil anything in just yet.
"She's really kinda busy, too," Perry said. "We're both busy, but we've already planted the seed two years ago, and it's just all about that special one…because how disappointed would you be if that song came out and it wasn't that good? Sometimes you have to wait for greatness. I hope it'll be great."
You can bet Beyoncé will be among the first reviewers if and when it drops.