The "Part of Me" singer attended the UNICEF Snowflake Ball in New York City recently, wearing a tight, floor-length, semi-sheer navy Naeem Khan dress with a matching cape.
But Perry admitted she didn't feel as good as others thought she looked.
"I feel like my [fat] is sticking out so bad right now. I almost always wear [Spanx], but not tonight, and I feel it pushing out, making me look fat," said Perry.
"I like to say I run on the elliptical for 30 minutes watching CNN, but I don't do it often enough. So I'm just like, 'Oh, I guess I'm not fitting into this Lanvin dress for these couple of months'," she added.
