The Perry-Pattinson romance rumors began swirling back in May after the "Twilight" actor broke-up with girlfriend Kristen Stewart.
"He's my bud, I'm like his big sister. We just hang out. The other day, I said, 'One of the things I'm most proud of is not sleeping with you, Robert.' And that's true," Perry told Elle magazine in an interview.
The 28-year-old singer earlier revealed that she cleared things up with Stewart through a text message.
"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..."