It was reported that Katy's reps had asked for her boobs to be toned down for the poster, but the 26-year-old says otherwise.
The wife of British comedian Russell Brand took to her Twitter page on Friday to explain what happened.
The Firework singer wrote: 'I was the one who asked VH1 to tone down my DIGITALISED image on the poster, particularly the size of my chest.
'I don't have handlers... but someone @VH1 offices is a gossipmonger & thought they could use a little extra press planting the story.'
Perry looked red hot in a tight catsuit when she performed at yesterday's American Music Awards.