Katy Perry explained that she sees Robert Pattinson as a younger brother in the September issue of Elle UK. Credit: Jason Merritt/Getty Images; Fotonoticias/WireImage

Katy Perry has an interesting way of, er, clearing the air when it comes to the rumor mill. The "Part of Me" singer told the September issue of Elle UK that she can prove once and for all that she and pal Robert Pattinson are truly nothing more than friends.

"Okay, so here's the proof there was never anything going on with me and Robert Pattinson," the pop star told the publication. "I fart in front of him. Properly fart. And I never, ever fart in front of a man I am dating. That's a rule."

Perry, 28, and Pattinson, 27, were first linked as love interests following his breakup with longtime girlfriend Kristen Stewart back in May. But, the singer explains, the pair have been friends for a long time, and their relationship is more a familial one than a romantic one.

"He's my bud, I'm like his big sister," she said. "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."

In fact, as previously revealed, Perry went so far as to text Stewart, 23, when she and Pattinson were first rumored to be dating to make sure that the situation didn't get messy.

"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,'" she recalled. "I'm just trying to be a friend to him, but it is unfortunate that I do have a set of tits."

Plus, Pattinson seems to have found love with another famous face -- a woman with major pop royalty roots! As Us Weekly exclusive revealed earlier this week, the Twilight hunk has been "hanging out and hooking up" with gal pal Riley Keough, whom he met through her mom, Lisa Marie Presley. (Riley's grandfather is the late Elvis Presley.)

"She's the first girl he's like since Kristen," one insider told Us of Keough, 24. "[They're] having a lot of fun."