Not content to rely on Vogue's photoshop team to her make her look cover-worthy for the fashion bible's July issue, Katy Perry went on an extreme three-month cleanse to prep for her Annie Leibovitz shoot.

The pop star told Jay Leno on Friday, "I did a lot of my own prepping... I kind of went on a cleanse, I did a lot of stuff like vitamins and supplements, I changed my coffee to green tea, I didn't drink alcohol for three months." She continued, "I was really in the zone, I just wanted to be glowing for that cover."

And when she says she "did a lot" of vitamins and supplements, she means it. US Weekly alerted us to a tweet from Perry mid-cleanse back in May, in which she's holding up giant ziplock bags full of 'em--we're talking Suzanne Somers style dosages.

Think it paid off?