Tallulah Willis, 20, starts the clip fully dressed, and eventually strips down to just her underwear while she talks about her troubles, revealing she was diagnosed with the condition as a teenager.
Willis claims she deliberately dressed provocatively and starved herself to stay thin.
In the footage shot for Stylelikeu.com, she says, "I struggled a lot when I was younger... I'm diagnosed with body dysmorphia... (I was) reading those stupid f***ing tabloids when I was like 13 and feeling like I was ugly... It was just a conviction... That made me dress like I was showing off my boobs and my butt and showing off those things that I was getting attention for... It took me until a year ago (to get better)... I was trapped in this body... and I hated that I was sexy... I started starving myself and losing a bunch of weight and I got down to like 95 pounds... When I lost my curves and when my boobs shrivelled up into like nothing and I had no shape. I was just saggy skin everywhere... It put me in even more of a cage."
Willis' confession comes just weeks after her elder sister Scout was pictured walking around New York City topless as part of a campaign against Instagram.com's no nudity policy.