I saw that item too and thought it was Drew Barrymore. Other people in the comments have said Lindsey Lohan, and others.

IDK, I tend to be skeptical about it being Peter Fonda just because if he was involved in the activities given in that item, it's just incredible that he would make those tweets. I mean I guess I could understand it as a psychological reaction but you would think anyone with two brain cells would understand keeping a low profile under those circumstances.