I was amused to see this NYT interview in which actress Helen Mirren talks about taking her mother to a day of shooting for the movie Caligula:

No, it wasn’t in the orgy scene. But you know, when we were doing “Caligula,” it was very rare that anybody had any clothes on. My mum was just great — she’d just sit there surrounded by all these naked extras or people wearing just little wisps of something or other and just chat away with everyone. That was a great quality my mum had.