Watson was in a movie that I can't think of the name at the moment, but she was naked in a bathtub. Nothing was clearly visible, but there were a few frames where her nipples were indistinct under the water.
I go to the same University as Emma, lol. I met her once - she's surprisingly very down to earth. Anywho ...
Honestly, idt Emma would ever have a nude scene. Considering the image she's built up over the years and the "coming-of-age" roles she always seems to be taking, the whole idea is just highly unlikely. And, if it ever came to be, I'm afraid you'd have at least a decade to wait, my friend.
Jessica Alba, on the other hand ... I could see it happening. Of course, you wouldn't see it all out there though, rofl. That's not how cinema works! Again, I could see it happening, but hasn't yet ... & you'll never see her all out there, so keep dreaming for now. ;D
