"I say more power to her. She is such a role model for millions of girls in the world and she should be whatever weight she wants to be and nobody should have to starve themselves," Kirstie said.
"I mean there are women - I don't know many of them - but there are women that are naturally thin - it's rare.
"And sometimes when you first come out in the industry and you have an image and you're all skinny and you have all this fashion and you become an icon because you're a stick and then - she gained what 30lbs? Who cares!
"I think it's good that she's saying this and starting the body revolution. I know dancers and ballerinas... I was talking to Shawn Johnson about gymnasts who are expected to be shredded and skinny and there's no way to do it naturally."
As RadarOnline.com previously reported, Gaga posted a series of photos of herself in her undies Tuesday as a way of launching her new campaign.
"Today I join the body revolution," she captioned one pic. "To inspire bravery and breed some m$therf*cking COMPASSION."