American Idol Tweeted THIS PHOTO.
Buy the exact same dress that Katy Perry is wearing here:
Katy is wearing the Carolina Herrera Polka Dot Ruffle Gown. Buy it here: FARFETCH, NEIMAN MARCUS, MODA OPERANDI, and THE YES
Get the look for less here:
Katy Perry's ruffled polka dot gown from American Idol