'I lay on my back one night and looked down at my feet, and I prayed to God.' admitted the star, who was raised by pastor parents.
'I said, "God, will you please let me have boobs so big that I can't see my feet when I'm lying down?"'
And Katy's prayers were obviously answered, with the star boasting an enviably curvaceous figure.
But even Katy admits her assets did not come out exactly as she planned, saying: 'I had no clue they'd fall into my armpits eventually.'
The Firework singer also came clean about any rumours of her having plastic surgery, firmly denying to having anything nipped or tucked.
'Never…not a nose, not a chin, not a cheek, not a tit. So my messages of self-empowerment are truly coming from and au natural product.'
29-year-old Katy also discussed the fact that she believes in aliens, and that she wants to ask Obama about life on other planets once their relationship gets better.
'I look up into the stars and I imagine: How self-important are we to think that we are the only life-form?'