London (CNN) It was a provocative photograph, like so many of Annie Leibovitz's before it: comedian Amy Schumer baring all -- or almost all -- for the 2016 Pirelli Calendar.

"Beautiful, gross, strong, thin, fat, pretty, ugly, sexy, disgusting, flawless, woman," Amy Schumer tweeted when the photo first went public.

Given that announcement by the subject herself, it may come as little surprise that Schumer was prepared for an even starker image.

"I think I forced her to put the underpants on, because she would have done it completely, you know, in the nude," Leibovitz, with a laugh, told CNN's Christiane Amanpour this week.

"She's really smart. She knows what she's doing."

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