Katy Perry farts in front of Robert Pattinson

The 28-year-old singer was rumoured to be romantically linked to the 'Twilight' hunk just weeks after he split from his co-star Kristen Stewart, but the brunette beauty is adamant they just have a sibling-like relationship because she's not afraid to release flatulence around him.

Speaking to the new UK issue of ELLE magazine, she said: ''OK, so here's proof there was never anything going on with me and Robert Pattinson. I fart in front of him. Properly fart. And I never, ever fart in front of any man I am dating. That's a rule.''

However, despite Robert - who spent a week at Katy's house following his split from Kristen - being voted the sexiest celebrity man alive last year, the 'Wide Awake' hitmaker is PLEASED with herself for not bedding the actor.

She explained: ''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.''